After an adware crisis, I reformatted/restored my HP Pavilion a640n which runs an AMD3400, 512MB RAM and 160GB hard drive with XP Home. Everything worked perfectly until I completed upgrading XP Home to SP2. The PC will not do a RESTART. Mo antivirus software running. It works fine otherwise, but want to understand what SP2 does to kill the ability to RESTART. Can I resolve this. Thanks.