Clean Windows

Is your Windows installation looking flaky? Don't worry - we've all been there. With so much interesting free software to download or install from cover discs, it's all too easy to install one app too many.

Before you know it, your hard drive is overloaded with unused tools that seem to conflict with each other. Windows gets slower and strange messages start appearing, warning of impending doom. Eventually, you have to bite the bullet and reinstall the OS.

At this point you probably vow never again to pollute your PC with strange software - that is, until you run across another tempting beta. One more won't hurt, will it?

Adding and removing software should be easier than this. Updated versions and programs constantly appear on the horizon, and no one uses the same programs forever. So why do we have to worry about the consequences of installing and uninstalling? It comes down to two very important components underpinning the Windows OS: the registry and the DLL (dynamic link library). Both these components run invisibly behind the scenes, but when they get screwed up, they get screwed up good.

The Windows registry is a database where all the settings and options for the Windows OS are stored. This information - known as keys - used to be scattered in folders all over the place, so there's an advantage to keeping track of it in a central place such as the registry. However, if the registry becomes corrupted, it can paralyse your entire system and force you to wipe everything.

Although the registry accum­ulates a lot of unnecessary junk that slows down your bootup time, it's incredibly risky to start deleting stuff from it willy-nilly. Get rid of the wrong key and your favourite program - or even the whole PC - will never again start up in its current form. To get at the registry, run Regedit - choose Start-Run, then type regedit. But again, don't start messing with it unless you know exactly what you're doing. You. Have. Been. Warned.

At the very least, it's a good idea to have a backup before you start making any changes, so when the registry editor is open, click File-Export, choose a name and location for the file, make sure that the "All" radio button is selected, and hit Save. That way, you can reverse any changes you've made if you need to, simply by double-clicking on the backup file and clicking on Yes when asked if you want to add the information.

A far less risky and much simpler solution to tidying up your registry is to try out a special cleaning program. I'm keen on EasyCleaner 2.0, available at or on the Cover Disc of the July 2006 issue of PC World - see Figure 1. EasyCleaner scans your registry for junk and then allows you to delete it, or dump it in the recycle bin, where it can be retrieved if you later find out it was important.

The other Windows component that can come unglued while uninstalling software is the DLL. If that acronym sounds familiar, it's probably because you've been asked whether or not you want to delete DLL files every time you've uninstalled a program.

In short, DLLs are files containing important pieces of code that can be shared by multiple apps. By sharing this code, disk space is saved and software patches can be made smaller. But this practice has led to so-called "DLL Hell", where apps start fighting over which version of the file should be used - video editing applications, in particular, are notorious for this.

If you delete shared DLLs while uninstalling a program, you could mess up another app that still needs it to run. As with unnecessary registry keys, unneeded DLLs will slow down system performance. Microsoft's .NET OS got rid of shared DLLs entirely, allowing multiple versions of the same code to coexist peacefully.

Good idea, but until the Windows platform does the same thing, you're stuck with trying to figure out what you need.

A quick and easy way to do this is to download a tool such as Clean System 1.7 (you can get it from or off the Cover Disc of the July 2006 issue of PC World) - see Figure 2.

It scans your PC for all DLL files and then removes any unused DLLs from the system directory and puts them into a backup folder.

Because these backed-up DLLs don't take up much hard disk space, it's a good idea to hang on to them for at least a few months - permanently would be better - in case some seldom-used application suddenly needs one and you have to restore it.

But what if you've already deleted the wrong registry key or DLL, or are worried about doing so? Windows does have a few tools to save your bacon. Unless you've specifically disabled this feature, System Restore will regularly create a "snapshot" of your PC's settings, allowing you to roll back your system to the most recent known safe state. If you're installing some software you suspect might be flaky, or want to try cleaning up the registry, create a restore point before you start. Choose Start-All Programs-Accessories-System Tools and then System Restore. Here you can create a snapshot or restore from an older point - see Figure 3.

Some programs offer a repair option to try and fix the damage from deleted DLLs. In Word, choose Help, then Detect and Repair (see Figure 4). And if the worst happens and your system is really ailing, you can try booting into Safe Mode - press <F8> when the Windows screen comes up while booting - and choose "Last known good configuration". It just might be the ticket.

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Susan Pederson-Bradbury

PC Advisor (UK)
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