Well, that shows your CPU is unstable then. I can quite easily open programs and swap between them when I am running Prime95, and I have a single core.
You may be able to swap the core it is running on if it isn;t utilizing both.
I think the ctrl. alt. deleting it may make the PC hang, you can try it though.
See my thread for overclocking. Gaara gave some tips for what to do, you can try them when you go into the BIOS.
Cisco CCNA, Comptia A+, 1/3 through CCNP