ok this step by step guide worked, but cut my raid0 into 1 drive for xp and the other for vista.
so i had a dual boot rig but lost my raid0

here's the guide, scroll up..
http://apcmag.com/5023/dual_booting_xp_wit...a#comment-37916


now i have 2 drives in raid0 on one array and another 2 in raid0 on the second array.

i guess load xp on the first, and than boot from the vista cd and install it on the second array?

the guide says nothing about raid.

Install XP on the first raid and then remove the drives from the system before you install Vista on the second raid. When the Vista install completes, replace the XP raid drives. If you don't do this, Vista will modify track 0 on the XP raid and all hell breaks loose. You won't get true "dual boot" functionality, as you will have to change your boot preference in BIOS, but I think you'll find it actually works.

awesome! tnx dude!

worked fine, and no need to enter the bios to choose the OS each time.
when i boot i just hit F12 and get a boot menu and just pick array 1 for xp or array 2 for vista.

tnx again..

That's a pleasant surprise. I would not expect it on all motherboards, but if if works for you, COOL!