XP home cannot find file i386

Hello,

I have a Compaq which came with XP Home Edition bundled on it (and yes it is legitimate and I have the product code). Due to a NASTY worm that I could not eradicate, I had to do a total restore (used all three COMPAQ discs provided) NOW the I386 file is nowhere to be found. This makes it impossible to run the function "SFC /Scannow". I am trying to get this doggone thing running faster than my OLD computer from years ago which came with Windows 3.1. Since the restore this machine IS SLOW...I have run defrag, I have run registry mechanic, I have run McAfee, I have run three different spyware programs, but I cannot recover any of the speed that this computer used to have. Any advice?

Thanx, Matt