Aiglon,
I would be very leery of trying to upgrade a Compaq PC. Compaq and Dell are notoriously non-standard in their component designs - no problem with hard disks, CD / DVD drives and memory, but not processor / MOBO upgrades.
I may be wrong, but I very much doubt that you will be able to get a MOBO for a Compaq other than from Compaq - now HP. And that will not be cheap!
It is not just the physical arrangement of the board and the location of the external interfaces, but also the board power connectors and voltages.
I hope I am wrong (I know nothing of the Compaq Presario Home PC range), but I know a lot about the "Corporate" Compaq PC. If it is a Deskpro - forget it! As a matter of interest, what is the PC in question
Having said that, do bear in mind that the HD disk controller is mostly on the HD itself - have you checked the cables to the disk / tried another HD / checked the disk in another PC? It is the IDE interface controller that is on the MOBO. In my experience, the drive is 100 times more likely to fail than the MOBO.
SD