Why does my computer reboot it self when i try to overclock my processor?

Probably because you don't know the first thing about overclocking. A 3.33GHz overclock is INSANE. I'm willing to bet you're using a stock heatsink. As such, your computer is severely overheating and reboots to prevent damage to the CPU. You probably never actually did get a successful 3.33GHz overclock.