I just installed a new CPU for my friend's computer (I've done this several times..not sure what I did wrong today) and after I turn it on and hit the power switch, it keeps beeping. (1 Long, 3 short) I googled it and it was a memory problem. We removed the ram, used the compressed air.
No go, so we removed the CPU, blew compressed air to make sure no dust.
It kept beeping.
We put back in the old CPU and it worked like a charm.
The board BIOS may be too old to recognize the new chip. Go to the motherboard manufacturer's website, find your MB and look up the CPU support list. See which BIOS is req'd for your new chip, and see which one you have. If your current is not equal or more recent, then you'll need to update the BIOS first.