New Intel 5200 won't boot

Just installed a new Intel E5200 in a Dell E-520 and it wouldn't boot, had to put my old chip back in, whats the problem, is the chip just DOA? Please help.

You're MB probably doesn't support 45NM chips with its current bios. You might be able to flash the bios to a newer revision and it may work, then again it might be too old and not have any 45NM support.

Did it work?

I think it should be noted that usually pre-made, big-box type of computers are not known to be that upgradable. While they don't produce the motherboards for their computers, they do have BIOS's writen for them. This will probably leave new CPU's in the cold when it comes to upgrading. It also leads to decreased overclocking or other BIOS options.

In short, I would bet money that a Dell can't accept a new CPU... even a similar one with a new stepping would be asking a lot.