I have an old Dell Dimension which I put back into service after sitting for a couple of years. I decided to put 2 X 512mb’s of ram in instead of the pultry 256 I had been running. Guess what? Same symptoms that the OP had. No beeps at all...fans would power up for a couple of seconds, then go off, then come back on. In my situation, I swapped the Partiot PC3200 out with some PC4800 I had....and the system booted up. It surprised me too.