My computer keeps staring up and shutting down on a seemingly endless loop unless started in safe mode. I have no idea how this happened or what to do. I've run my virus scan and ad-aware, but nothing's helped. Anyone got any ideas?

Hi has this happened recently? Try a system restore to before it started looping.

Through the All Programs menu:
1.
Click Start.
2.
Point to All Programs.
3.
Point to Accessories.
4.
Point to System Tools.
5.
Click System Restore.
6.
Follow the instructions on the wizard.