Coarsely an OS becomes tied to a motherboard, due to factors like chipset drivers etc and if you change the motherboard you may have to do a complete reinstall. BUT if you are changing over to a new motherboard and you follow a guide like this, with the new motherboard Chipset Drivers on hand it can be achieved:
How To Change Your Motherboard - OverclockersClub Forums
Otherwise it wont matter whether it is RAID or just a normal DATA HDD if you don't follow a guide like this you generally have to do a complete reformat and re-install unless certain parameters are true:
1. It is exactly the same make and model of motherboard, and or
2. It has the same "Chipset"
I personally like the "rebuilding" of the OS method used by Fred Langa, not sure if this works for Vista I'm afraid;
Langa Letter: XP's No-Reformat, Nondestructive Total-Rebuild Option -- Windows XP Management
Read it twice so you understand the method properly.
As pointed out by Mars please back up any and all crucial data and hopefully that should work for you.