A good place to start would be by posting details of your problem to a
newsgroup supporting those running XP rather than one supporting those
running Win Me.  When you do post to an XP newsgroup remember to provide
full details of the messages seen when you attempt to use system restore,
something you omitted in your message to this newsgroup.  It would
probably be helpful to those who might want to try and help you if you
also include full details of the AV application you are running together
with details of the spyware it told you you had installed when you ran the
unnamed file you downloaded.