My computer keeps shutting down..Sometimes it will stay up for hours then other times it shuts down almost as soon as i get on it and keeps going on for hours or more..Can it be a video card or any ideas at all let me know ok? The fan is working on it i did check that.It does re boot everytime right away and i get on line and it goes again..now its been up for hours so who knows!

Could be either the battery wants replacing
Bit fiddly job
Or its in need of a clean out (build up of dust /fluff clogging the cooling fins and fan blades leading to occasional overheating (computer cuts out suddenly)
If the Battery is in need of replacement the computer clock will start showing wrong times and the Calendar resets to 1980 (Also the BIOS screen starts showing often)
Tools for cleaning small screwdriver to open the grilles and a cotton bud and a piece of damp Kitchen or toilet roll (wrap arong the cotton bud )
Can blow a lot of the muck out using a pen tube without the pen inside and blow through the "big end" and if you can find one a rubber tube over the end of this "tool" will let you aim the air more accurately
PS The Battery Looks like a large watch battery
and replacements can be found in Photography Stores or Pharmacy stores
Check the number before you buy (Have a Peek in the computer case)There are several different types, and prices do vary between stores for the same item
Once replaced you'll get a few years service with no BIO messages or Calendar Resets

Hey, Sammy, mine started doing that just before my harddrive died.

Thanks both of you but this is not my laptop its my desk model...anyhow, my brother did something to it and now its staying on......again..its done this off and on...sure hope its FIXED this time!