Recently, I've been trying to create a multipurpose Bootable DOS CD to aid in diagnosing and repairing simple PC problems. So far I've managed to add USB support, long file name support, and a host of DOS utilities. (I have a boot menu to enable or disable these features.) And I can get it to boot successfully in most modern PCs. HOWEVER, I want this boot CD to be UNIVERSAL and for some reason I can not get it to boot at all in old PCs such as my ATX unit with an ASUS P5A mainboard - even though boot from CD is enabled in the BIOS. It just skips the CD and boots straight to the C: drive.