Inspiron 6000 won't power up.

The "A" (caps lock) light flashes 10 times and that's it. The unit will not power up at all. Everything was ok, we were just useing the computer. I found a small screw that had fell out of the back of the computer, so I turned it off and  I tightened up all the screws and as an extra measure removed and reinstalled the hdd, mem chips and dvd drive. Now this!!! I've already tried taking all of those items off and reinstalling them again. Still nothing. I've tried power up the unit after installing each item one by one and by the time I get to the mem chips the "A" just flashes.

 

HELP!!!!!:smileymad: