I recently had a similar issue with a Dell server running SBS08, so I feel your pain.
- Check your RAID integrity. Do any of the drives have amber lights showing? If you go into the RAID utility, does it say your boot drive is healthy? Correct any errors there.
- Check your RAID card. Did something get jarred loose when you moved it? Reseat the RAID card and all drives. Make sure all the connections are good.
Boot off your install CD (which I assume you did, since you're running chkdsk on the non-booting server, so if you did skip this step). Verify that the drive is visible. There's also a repair option, which you might need to avail yourself of (and also a restore option that works with Windows Backup, but before you do that...).
- If, after all that, it still won't boot: Call HP and get them to send you a new RAID card even if all the previous things claim to be okay. I recently had an issue with a dying RAID card that showed healthy, but the drive was unable to find boot files. I don't know about your warranty, but it might be worth your while to cough up for the warranty just so they'll send you a part and someone to put it in for you. (Yes, you can put it in yourself, but the guy who does this every day is less stressed out than you are right now.) If they give you any attitude, say, "I have four hour gold support [or whatever] and I want a RAID card."
If all that fails, you might need to run a repair off the install CD or restore from backup.
Edited for your comment about repair BSODing--this is almost certainly a storage issue. Even if your RAID claims to be healthy, get a new card and see if that resolves your issue. (It did mine.)
Good luck!