What is your processor and what kind of ram are you using?
Usually, those motherboards are proprietary to Compaq and you will have to go
back to Compaq to get a replacement. Things that are proprietary might be the fan headers, I/O back plane, power supply, the holes that screw the motherboard down to the case, and heat sink attachment. So, if you replace the motherboard, you might have to replace a lot stuff too.
Edit:
I just checked and that motherboard is a socket 754 motherboard and uses DDR ram.
It's really hard to find a motherboard for that CPU nowadays and DDR ram is too expensive.
You'll save your self time and money by just getting a new computer.