re: CMOS
Most basic settings can be accessed by pressing a certain key during the intial startup process. Also, depending on the motherboard, you can load a new bios from a floppy disk, and I've upgraded mine a couple of times. The bios your board is using is usually readable in the setup area that I just described.
The bitch is figuring out who actually made the motherboard, especially in off-the-shelf computers. I bought my board special, so it wasn't hard for me. Once you figure that out, bios settings are usually downloadable from the board manufacturer's website.