OEM Windows and RAID

My Mom's computer has 2 hard drives, one 500 Gig, and one 750Gig. The OS is installed on the 500 gig, and has been reinstalled on that drive for about 2 years. As well all know, OEM OS's can only be installed on one hard drive. Now I'm wondering if I can RAID those two drives, and still install the same OEM Windows Vista on the two hard drives. Will that work?

It would probably work. Since as you know raid emulates one hard drive, it probably wouldn't know the difference. No harm in trying I suppose.