Back again, guys!

I've been using Adaware, but recently downloaded Spybot. It seems to catch more. Anyway, I've run it and it has successfully removed everything it's found except for this one file. I keep getting the message that the file is in memory and will be removed when I restart my computer. Been there, done that. It's still there. I also tried a manual removal with Quickclean, but got the message that the program was in use when NOTHING was in use. Spybot says the file is this
C:\WINDOWS\SysUpd.exe. I think this is what's responsible for constantly changing my homepage. Any suggestions? Amy?