I have been trying to format my pc and reinstall windows xp pro (which is already on the computer) but it wont boot the xp pro os from the disk even thouth its the same disk that installed the one currently on the system and the system is set to boot from cd.what it does is ask to pres any key to boot from disk and when i do it boot up system normally instead of the running the os on the disk.can someone please help me?