Basically, lately my computer has started switching off by itself. It switches off completely and then if i switch it off by the plug and back on again, it comes back on with a message saying 'error occured in monitor hard drive/disk' (can't remember the exact words!)..and then it says press f1 to continue or set up menu..i press f1 because i don't know a thing about computers and my computer starts to work propperly again. My dad has changed the sockets in my room and the extension lead but my computer still does the same. The fans are working and i don't put the cover on my tower anymore so that air can circulate in the tower. And now and then i pull my tower out and put a fan on infront of it (on really sunny days).
Some days it swtiches off more than others and it tends to swtich of at night..not during the day.