beeps 3 times at start up and won't boot
What does it mean when the LED blinks and the computer beeps 3 times but won't boot? Thanks.
I agree too, sounds like memory at fault.
Check the memory you're trying matches the speed of the original. If it's got more than one memory slot, try both, and if possible, blow into the memory slot to clear out any dust that may cause it to make bad contact deep inside.
I have a DELL 6400 here with me now that's had that problem, I fixed one part and rebuilt it, but dust/fluff was all around a RAM slot and some got pushed inside causing the memory to fail randomly. It's been running fine for 5 hours since it was cleaned with an air-can.