Hi symandoy,

Have you tried booting into safe mode (tap F8 at boot)? If booting in safe mode is successful then the driver or service causing the problem needs to be identified. We can provide more detail on troubleshooting this if necessary.

Also you could try booting in safe mode with network support. If this is successful try downloading and running a malware scanner such as Microsoft Safety Scanner.

http://www.microsoft.com/security/scanner/en-us/default.aspx

Rich