|Why do you think you need a mboard?|
When your system isn't working right, that usually is one of the least likely things that could be defective.
Tell us all the symptoms you can come up with if your system isn't working right.
If your power supply is a BESTEC model, they are well known to fail more often than average, and when they fail completely they are more likely to have damaged something else while failing.
Failing power supplies are common and can cause your symptoms.
Check your PS.
They often partially work, fans and hard drives may spin, leds may come on, yet you get no video and the mboard will not boot all the way.
See response 4 in this:
If you mean for the V5305wm system, Compaq doesn't make the mboards - they're supplied to them by major mboard makers. They're either identical to models made by the mboard maker with a Compaq bios version, or they're OEM only versions made only for the brand name builder ( or several brand name builders) with a Compaq bios version.
Usually the mboard model is printed in larger characters on the surface of the mboard, often between the slots or in the middle of the mboard, but sometimes with OEM only mboard versions that's not there. There is a sticker on the mboard with the Compaq (or HP) part number for the mboard on it, it often has a bar code on it too - 9 numbers/letters -xxxxxx-xxx - quote that if you can't find an obvious model number.