Be unhooked from the Internet until you confirm your firwall is on, then
re-install SP2.
Direct Download of Service Pack 2 (SP2) for Windows XP http://snipurl.com/8bqy
It may or may not! A repair install killed my puter using my XPHome
w/SP1 disk after I had installed SP2. Once I made a new disk with SP2
slip-streamed in, the machine worked again. I suspect some remnants of
SP2 got left behind with the first repair install.