Windows 7 doesn't know how to deal with the RAID setup so back to Dell to find out if they documented the OS pre-install setup and then the actual OS install. I don't own this one but have had to research such on many others a lot of times.
The most common is that I have to prepare the RAID prior to the OS install (very machine specific) and then have some CD/USB of the drivers for the RAID to have handy during the OS install.
While I don't mind all the work I worry that RAID in consumer models will cause big support bills.
I have a Dell Studio XPS 8100, running RAID0 and lost a HD. I replaced both HDs with two larger WD 1TB hard drives. I have both the OS and Drivers CDs that came with computer when new. In an effort to keep this from happening again I change the RAID to RAID1 in the BIOS. When reloading the Windows7 near completion I get a message "Windows Setup could not configure Windows to run on this computer's hardware." I've tried reloading the Drivers, but get a message "Drivers not found". No new hardware has been added to this computer other than the two WD hard drives. Any suggestions as to how to get the OS system loaded and running.