A clean format and install are often quicker than messing with a lot of infections. Just make sure you run a good virus and spyware scan on the files you back up.
Sometimes the removal of spyware messes up your Internet connectivity because registry entries get removed or corrupt. A free program I have used in the past that has worked well is
Winsock XP Fix.
Good luck!
Other links:
http://www.iup.edu/house/resnet/winfix.shtm http://www.cit.cornell.edu/computer/...re/repair.html