This page offers information on dealing with restoring the computer to a previous configuration: How to restore the operating system to a previous state in Windows XP Those directions seem to make the process a whole lot more complicated than it actually is. If I had Windows in front of me, I could simplify the directions. The process is pretty self-explanatory once you get the Restore thinger opened up. Depending on how far back you go, if you've installed software recently, that software may break. That's because that software's registry entries would become unavailable. If that happens, simply reinstall that piece of software. Note that restoring the system to a previous configuration doesn't remove undesirable software; it simply makes it non-functional. In addition to Search & Destroy, you can install and run this: Ad-Aware 2007 Free. I haven't tried this personally, but SpywareBlaster prevents malware installation without running processes in the background. It disables entries in the Registry that allow junk to be installed. Chances are you're already covered with this, but it's also a good idea to not use Internet Explorer. It's just not safe unless you have a good understanding of anti-virus software, anti-spyware software, and various controls scattered around the Windows operating system. Firefox and Opera are excellent browser alternatives. Additionally, Apple has released a Safari beta for Windows. Another very good idea is to run Windows as a Limited User rather than as an an Administrative User. (I even do that on OS X.) If you're running as a Limited User, malware will find it much tougher to install itself.