BIOS (Non-KeyBoard) Problems

So, I've been trying to format my PC, and my computer won't boot from the XP CD so I can do it the easy way. (My floppy drive doesn't work, to get that section out of the way)

I've tried to go into the BIOS to set it to boot from CD, however, no matter what key I hit it only starts Windows up.. (except F8 asks me what operating system to use, though there's only one option)

Then, finally, if I try to just install from disk with Windows running, it says that I have a better version of windows and I should just be satisfied with that.... so... yeah...

Any clue?

Be sure to use an XP SP2 Slipstream disk. I don't know how long ago but I remember using either a 2K or an XP disk at some point that didn't support booting from the CD.