I didn't notice an ich xx or nvidia raid or something similar in your motherboard specs. I don't quite understand why there would be a bios setting for a raid that doesn't exist?
If it helps, we worked through a mixup relating to windows 7 and the intel matrix storage manager in this thread.http://www.tomshardware.co.uk/forum/258542-14-boot-drive-raid0-games-setup
The thing is that win7 sets up the drivers for AHCI, RAID, IDE, or whatever you have set in bios when win7 is setup on your system. If you want to change from, or to, AHCI or RAID later, you need to tell win7 BEFORE the change.
Check the thread and you will see a link to a 'FIX' for this issue about 4 replys from the bottom.