Cant Reformat

I tried to reformate my computer but put on the wrong version of windows. I had a nasty virus that crashed my windows. Thats the reason for reformating it. I need to figure out how to use my recover disks i made for windows xp to reformate my computer. When i start the computer with the disk in it, the computer ignores it. I tried to run the disk and it only runs a install program for the mouse hardware. The computer is a compact presario 58 Mb mem and 420 mb ram. The windows installed currently is e-machine windows 2000.
I need help please!!
Billy