It sounds as if your antivirus or spyware software has deleted any infected files found and made the restore points useless. Microsoft has a knowledge base article 307545,which describes a tedious fix. First though you could try booting from the Windows installation disc (you may have to change the boot sequence in the BIOS), & at the blue screen press R to enter the Recovery Console. Oh, you will need the Administrator Password which hopefully you chose & remember!! Type chkdsk & see what it reports. Then try chkdsk /r (note space between k & /) which can take a while appearing to not do alot, but it cured a startup problem for me when all else failed. Don`t use any of the other DOS commands in the Recovery Console unless you know exactly what you`re doing - find out about them first!