check your bios, make sure it's still set to try to boot from CD-drive first.
yep, its set to that.
(to access bios read on screen prompts for setup, it could be one of the F# keys, it could be Del it could be Insert, w/e it is, you want to hit it repeatedly instead of holding it)
tried that too
you probably just need to do a repair reinstall of windows, since as you say, your pc is getting old so probably getting its share of HDD errors.
yeah i know, as stated i cant access the "boot from CD" option >:[
usually with other computers ive delt with, theres been prompts or signs of files about to corrupt. this was totally out of the blue. caught me off guard! lol