With the way Windows is designed, it tends to slow down after being used for a while thanks to the crunge that accumulates in various corners of the operating system. We’ve typically recommend blowing away the operating system and reinstalling Windows from scratch once every 6 months to one year; the main problem you may run into doing this on a regular basis is that Microsoft may wonder why you’re re-activating the operating system so often. If your system has been up and running for two years it’s no wonder it’s starting to act flaky.

And you’re right, we typically haven’t recommended registry cleaners — if they accidentally remove something in the registry that shouldn’t be removed, it can render the system completely unbootable.

If you want to try to salvage the system without reinstalling, try these in this order:

1) uninstall programs you don’t use any more in the Control Panel’s Add/Remove Programs section
2) if you want to use a registry cleaner, do it next
3) defragment the system to optimize your hard drive again
4) turn off services and programs that are running but that you don’t use; we recommend AutoRuns, from Microsoft’s SysInternals division: http://www.microsoft.com/technet/sysinternals/Utilities/AutoRuns.mspx

It’s a lot of work though — in the end it may be easier to reinstall Windows and your applications, and update both the OS and the applications again. And don’t forget to back up your user data!!