You need to ensure that all spyware, virii etc. are removed before installing SP2.
I would un-install SP2....remove all spyware and virii etc. then try installing SP2 again.
I have acer s series 210 desktop. when the windows update ask me to update to Windows xp SP2, I get many error in the installation. I get some error code 203 at 636E3EFD , 203 at 5A003CD1 and more! I go to search the error code but didn't found! when the window startup, there is a BLUE stick past through, not the green one! Because green stick represent SP1 and SP2 is blue! The computer keep on restart! Should i reformat the computer or have any recovory method?