Cliff's Notes version:
A.) Download, install and update
the free version of Superantispyware while booted up in normal mode.
B.)
Turn off System Restore. This deletes old restore points which could have malware hiding in them.
C.)
Reboot into Safe Mode and then scan the system.
Longer Version:
Use
IzArc instead of the WinRAR mentioned (If you need a compression/decompression app).
Use
Dial-a-fix instead of the Winsock Repair Tool mentioned.
The rest of the article is pretty spot-on.
Once the system's clean, that same article has some security suggestions, and I would also read and follow the
Secure XP page to prevent recurrences.