My desktop PC which is 4 years old shows no problems in the operating system (at least there's no such notification) but it shuts down immediately after a 15 mins work on Windows xp operating system and when I want to start it again I have to remove the power cable and put in again otherwise it gives no reaction the shut down or start button. The problem only occurs when I start windows operating system, it means that if I turn my pc on and not load the XP but keep it on BIOS mode it never shuts down.
What is the problem?? Is it the RAM memory, the Graphic card, the Power Supply Unit (PSU) or what??