Whether you can use system restore, depends upon when your machine was infected. It is possible the files with System Restore are themselves corrupted.
However, if you can overcome the initial problem of cleaning your machine, in theory at least, you should be able to use the system restore facility. Incidentally, you would be well advised booting into Safe Mode, and disabling the System Restore facility, BEFORE you try and clean your machine.
Run the tool from a write protected floppy,with XP in Safe Mode.