|This can be caused by a number of things. Did you recently install any new hardware? Did you recently install or update a new driver?|
This can also be caused by faulty hardware, specifically RAM. Try removing all memory sticks from the computer and then re-seat them. Start the computer and see if the problem is eliminated.
If that doesn't do the trick, use process of elimination to determine which, if any, of the memory sticks is the culprit. Remove all memory sticks except one and start the computer. If your computer still doesn't work, remove the one stick and replace with another.
If your computer only has one memory stick, try replacing it with a memory stick from another computer.