OOOH wait I see what your saying, ya because XP doesn't have drivers already for AHCI but Vista and Win7 do.
Ya if you install Win7 first, and then XP. XP won't let you boot into Win7 without manually jacking with the hmmm I forget what it's called. Was boot.ini in XP, but it's called something different in Vista and Win7.
I pose this question though... why keep XP?
I tried to install win 7 64 and gets to a point it asks a cd for drivers, and loaded themobo drivers and no luck
Then I installed the win7 32 and everything is smooth. but have not entered the registration key.
Why win 64 won't work, I burned it on slow speed. and verified it in vista home edition, does my dvd burner must support a 64 bit. tia