At work I have a dev box PowerEdge 2800 which had Windows Server 2008 on a 34GB drive in a RAID 1 configuration. I quickly ran out of room with and needed to change it to a RAID 0 to get 68GBs.
I used Ghost 8 to make an image of the drive and restored the image to the new 68GB RAID configuration.
When I rebooted, I received the error:
The boot selection failed because a required device is inaccessible.
After doing a lot of searching, I came upon a number of solutions and I tried a couple but they didn't work either because of the OS or the solution was for only a part of the issue and didn't fully resolve it.
Anyways, I finally did the following from the different suggestions and it worked for me. Now I don't know if all of the commands were necessary but I ran them all because I didn't want to reboot and have to run the next one. 
1. Booted with the Windows Server 2008 disk and went to the Repair Install
2. Selected the repair an existing install. (I had to load the driver for the RAID controller first before it saw the drive).
3. Selected the command prompt and CD'd to the boot directory on the Windows Server 2008 DVD,
4. I executed the following:
D:\boot\> bootsect /nt60 G:
D:\boot\> bootrec /rebuildbcd
D:\boot\> bootrec /fixboot
D:\boot\> bootrec /fixmbr
5. Rebooted.
That solved my problem, thank the Byte God
For info on the bootrec.exe tool go to http://support.microsoft.com/kb/927392