I can't quite see it from here. Could you post the computer or motherboard make/model, CPU, RAM, Hard drives, operating system?
Lets assume XP. Is Servive Pack 2 applied? All Microsoft updates? Is it a legal version?
What happened preceeding this? Any playing about inside the case or messing with the BIOS? What do you think happened? Are you the only one using the computer?
You mentioned thingw were tried? What and by whom? What happened there?
Just a few minor things like that. See below.