Can I change my BIOS CPU MHz setting?

[ensign]

Without permanently messing up my PC?
My PC freezes a lot. I'm thinking that if
I reset the BIOS to 266 (now 300) maybe it
will quit freaking out. I don't know why, I
just don't know what else to do.

[reboot]

Is your CPU a 266 or a 300? What is your bus speed? If your MB supports it, you could slow it down. If your MB doesn't, you have to change jumpers on the MB to slow it down. Could be inadequate cooling, or bad RAM, or too much overclocking...
Cheers, Jim

[Bleeding Edge]

It's not outright obvious but your at the end of the rope aren't you.

Why not start from scratch. Check all the BIOS settings, check all hardware connections, FDISK the drive(s), Format and reinstall the OS with just the video card. Update those drivers and install additional cards and drivers one by one. Then install one program at a time and update/patch them.

Stay away from Utility programs for now.

See what happens.