It's unlikely that the drivers required for the motherboard will be identical. Since Windows Home Server V1 is built on Windows Server 2003 R2, which is very similar to Windows XP, you will have the same troubles if you try to just change out your MB that
you would have with XP: probable bluescreen when you boot, a need to get drivers updated, general flakiness if it
does run without new drivers and possibly even after driver updates.
That said, you're already buying into reinstallation, which nukes the system partition, so all that is somewhat irrelevant. Instead, you will need to be able to get setup to present you with the reinstallation/recovery (depending on the age of your installation
media) option, which is dependent on your BIOS presenting the correct drive to setup as the boot drive, and is also dependent on you supplying the correct storage drivers to setup at the correct times. Much has already been written in these forums around this
topic (please use the search feature), but to condense it, you can give reinstallation a try, supplying the correct drivers at appropriate times. (You may need both Vista and XP drivers, supplied at different times.) If you can't get
the recovery option presented, give up early rather than late, read the FAQ (in the FAQ section) about recovering data from a failed server, and implement that by disconnecting
all your data drives, doing a new installation, then copying data back to your server one drive at a time.
I'm not on the WHS team, I just post a lot. :)