|Is that really possible? Well, I guess you can always open the case and find the 'clear cmos' jumper on the motherboard. Jump it to the 'clear' position, turn on the PC for a few seconds, turn it off and place the jumper back in the standby position. That will reset everything to default which should give you your boot devices--assuming nothing else is wrong.. You'll need to set the date and time too.|
Might also check the manual. If it's possible to clear those devices it may tell you how to re-enable them.