Please give system details.

hp amd athlon tm  64x2 dual core processor

  4200+    2.2 ghz  2.00 gb RAM   Windows xp I think I had sp3

sorry...   it's a D 630 dual core 2.2   1 gig of memory

Pull the drives (optical and hard drive), memory, wireless card(s), and battery and start it up.  It should give you the "can't find memory" error lights.  If it does anything else, its something with the motherboard or CPU, most likely.  Otherwise, put the memory back in and see if the problem comes back.  Add one peice at a time until either the problem returns (and shows you which peice is the problem) or you've put them all back.