Clean the Crud From Your PC

Fact: Your Windows PC is slowing down. Maybe it takes longer to boot up or shut down. Perhaps the hard drive grinds in the background constantly. Or maybe launching an application takes much longer than it once did. And although Windows 7 is speedier than previous versions, it can still become sluggish, particularly if you install and uninstall a lot of applications.

In this article I'll look at what it takes to clean the crud out of your system that has built up over time. I'll specifically discuss boot times, hard-drive issues, and the mysterious Windows Registry. I'll also explain how you can minimize problems in the future and change your crud-inducing habits.

Mysterious PC Slowdowns: Possible Hardware Culprits

Sometimes a PC will start to crawl without warning, and the reason isn't always obvious. Although the focus of this article is on cleaning and preventing operating-system gunk, it's worthwhile to touch briefly on a few hardware problems that can cause sudden slowdowns.

Vanishing Memory

If you built your system yourself, the BIOS may on occasion reset itself without your knowledge. This can happen during a power failure, or if you shut down the system during the POST process. During such a reset, the memory speeds may revert to something more conservative. You'll notice performance issues only when running memory-intensive apps.

Another possibility is that the apparent amount of memory might shrink. For example, on recent motherboards built with Intel's P55 and X58 chipsets, a heat sink that's too tightly mounted can bend memory circuit traces on the board. The net result is that one memory module becomes invisible to the system, potentially reducing the amount of memory available to Windows by one-third or one-half. That hampers your system, particularly when apps and data are swapped to virtual memory on your hard drive.


Modern Intel and AMD CPUs will automatically throttle down if they get too hot, which can happen if your system's CPU and case cooling fans become coated with dust and start slowing down. Be sure to check the system temperature in the BIOS, or with any utilities that may have shipped with your motherboard.

Imminent Hard-Drive Failure

As hard drives begin to develop bad sectors, they try to copy data to safe sectors. Ordinarily this occurs rarely--but when a drive starts to fail, the behavior could become more frequent. The net result is constant disk use, as the system attempts to find free, good sectors. If you suspect such activity, turn on the SMART feature in your PC's BIOS, which will pull diagnostic information from the drive and warn you if failure seems imminent.

Windows Entropy: Why Windows Gets Slower with Use

Now let's move on to Windows itself.

Windows slowdown has three main causes: The Windows Registry gets bigger, DLLs and other junk are needlessly duplicated, and hard drives become fragmented. One other cause on machines that have a lot of programs installed is that a lot of background services and applications can be running, without your knowledge.

These potential problems aren't mutually exclusive. The Registry can swell as you install more software, which in turn loads a lot of background tasks. Plus, your hard drive may fill up, making Windows auto-defragging harder. But let's look at these issues one at a time.

The Windows Registry

Windows maintains configuration settings, application install settings, and options in a database called the Windows Registry. As you install and uninstall applications or make changes to Windows, the Registry tends to grow larger and larger. For example, the Registry on my production PC, which has a ton of apps installed, is about 384MB--and that's just a backup.

As the Registry expands, applications and services that use it take longer to load. Searches conducted through the Registry by apps that may have written their data in multiple places also start to require more time. Some applications, such as security tools and certain media players (PowerDVD and the like), touch the data in a large number of locations.

The other culprit behind Registry bloat is incomplete uninstalls. Most users install or uninstall only a few applications per year, but some people (gamers and power users come to mind) tend to install and remove many programs.

Incomplete uninstalls leave residue in the Registry, which adds to its size. Windows 7 and its program uninstaller is much improved in this respect, but still not perfect.

As it turns out, however, Registry cleaners aren't really the way to go. More on that later.

Associated Application Crud

When you install applications, sometimes they need various runtime modules to run.

See all those separately installed copies of the Microsoft Visual C++ redistributable? You really need only the latest version. If you're running the 64-bit version, you might need two copies, one for 32-bit (labeled "x86") and one for 64-bit (x64).

This is just one example of the kind of junk that can get installed on a system. It's hard to stop and track down, and determining whether removing it might break something is often difficult.

Unneeded Background Services and Tasks

The more stuff you install, the more the programs seem to install some kind of service in the background. Maybe that service will speed up an application launch. Maybe it's a control-panel applet for a high-end gaming mouse.

Do I really need Impulse Now running all the time? I use it only when I'm running a game downloaded from Stardock's Impulse digital-delivery system, or when I'm buying a game from there. I certainly don't need it. And I rarely use Microsoft OneNote, so that doesn't have to run either.

Hard-Drive Issues

A machine's file system will become fragmented eventually. Windows 7 tries to minimize that by running the defragger in the background when the PC is idle. But if you frequently create and delete files (or use applications that create and delete files regularly), the file system is bound to become fragmented.

System-performance issues can also crop up if the drive gets too full. If a drive is more than 90 percent full, swapping from main memory to the drive becomes very slow, which can drag down the system as a whole. It may be time to clean out your drive--or buy a bigger one.

Incomplete Uninstalls

The Windows uninstaller--as well as similar uninstall apps that ship with some software--doesn't always completely remove an application. This shortcoming causes the Registry to balloon, leaves extraneous files on the hard drive, and otherwise cruds up a system.

Next: Diagnostic Tools

Diagnostic Tools: Tracking Down the Junk

You'll need some tools to help you unearth the excess files and other crud that may be clogging up your system. Here are a few.


Benchmarks help you determine your system performance. It's worthwhile to run a systemwide benchmark, such as WorldBench or PCMark Vantage, when you first build or buy your system. Save the results, and then run the benchmarks again every few months. If the results decrease by more than about 10 percent, you may want to clean out your PC.

Useful Widgets

Windows ships with tiny applets, or "gadgets," that you can keep on your desktop. Bear in mind that if you have too many gadgets running, they may slow down the system. One useful gadget is the CPU meter--not so much for its CPU-activity reports, but for its memory meter. If the percentage of memory used over time seems to increase substantially, you may have background tasks loading that you don't need.

Not enough? Grab some third-party system-monitoring gadgets from Microsoft's site.

Windows Resource Monitor

Gadgets are nice, but you'll probably find the Windows Resource monitor more practical for diagnosing potential issues. It's a substantial step up from the CPU-meter gadget, and superior to the more commonly used Task Manager. You run Resource Monitor by clicking Start, Run, typing resmon, and then pressing the Enter key.

For monitoring system-slowdown issues, you can always just watch the actual system-performance monitor. Perhaps more useful, though, is the memory monitor, which tracks memory usage. It even shows you, in a more granular fashion than Task Manager does, how a particular app or service is consuming memory.

Windows Reliability Monitor

All those memory-hogging and performance-sapping modules can make your system less stable, so be sure to check the Windows Reliability Monitor, too. You may think your system is less stable than it once was, but the Reliability Monitor will give you the data to confirm that suspicion.

You launch the Reliability Monitor by going to Control Panel, clicking on the System and Security link, and then selecting Action Center. You'll see a heading labeled Maintenance. Click on that, and you'll see the link for View Reliability History.

It's easy to navigate the Reliability Monitor by clicking on the columns that represent dates. You can also see the trendline, which may be flat or downward-sloping. (The sharp drop around 9/16 in the screenshot shown here represents my install of the Internet Explorer 9 beta. Prerelease apps often have reliability problems--no surprise there.)

A sudden, sharp drop is worth checking out. If multiple apps are shown to be unstable, maybe something you installed (or uninstalled) just before stability problems occurred is the culprit.

System-Boot Diagnostics

It's amazing how many applications, tools, and utilities attempt to preload something or another during boot. At one point I had a high-performance Windows XP desktop system that would take 15 minutes before the mouse would become responsive.

Windows 7 has fixed many slow-boot problems, but even so I've seen supposedly high-end systems take nearly 5 minutes to fully boot up.

One third-party program that's useful for assessing boot problems is Soluto, which is both a diagnostic program and a utility that can fix slow-boot issues. I'll talk about it at length on the next page, in the section on cleaning tools.

Cleaning Out the Crud: Multiple Options

You can, of course, manually clean out a lot of the junk on your system. Here are some ways to tackle the job.

Disk Cleanup

The past few versions of Windows have shipped with the Disk Cleanup utility, which you can launch by clicking Start, All Programs, Accessories, System Tools, Disk Cleanup. When I used this tool on my machine, I discovered 16.3 gigabytes of Zune temporary converted files.

You can manually clean out old system files, as well--but that can be perilous, so delete such files with care. Also, Disk Cleanup allows you (under the More Options tab) to delete all but the most recent System Restore and Shadow Copy files. I recommend avoiding that--you never know if you'll need an older restore point to get a usable machine back if you run into problems.

Defrag Your Drive

Defragmenting your hard drive is useful after you've performed a sweep with Disk Cleanup. During the defrag process, your system performance will slow down, since the defragger keeps the hard drives pretty busy. The Windows 7 defrag utility is somewhat smart about this, but your PC will still be less responsive during the process; it's best to run the utility when you don't need timely system access.

System Configuration Utility

This tool is more commonly referred to as Msconfig. You launch it by typing msconfig in the Run bar.

Using Msconfig lets you manually specify services to run, as well as startup applications. It's far from perfect, however: It doesn't give you any advice as to what services can be safely disabled, though you can hide Windows services, which makes the Services tab a little more manageable.

The Startup tab is more useful. The caution here, though, is that if you disable everything willy-nilly, some of your applications (such as your antivirus software) may not work. Still, stuff like the QuickTime Helper app and the Adobe Acrobat helper can be safely disabled.

Registry Editor

Use the Windows Registry Editor, aka "regedit," with caution. You could easily delete keys from the Registry permanently, and render your system unusable. A less serious risk is that you could make applications unusable, and then have to reinstall them. I've run into situations, however, in which a partial Registry edit makes it impossible to uninstall or reinstall an application--but the app won't run. If you're going to edit the Registry yourself, back it up first.

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