need help with vista/mse2005

I bought vista prem. and installed it on a new sata drive. before hand
I had windows xp mse2005 on another sata drive. I unhooked the drive
with xp mse2005 on it before I installed the new drive with vista on
it. everything installed fine vista is running fine at the time. so I
connected my xp mse2005 drive started up every thing looks fine I can
see and alter files on both drive. every thing is fine. I then unhook
my vista drive and try to boot to xp mse2005 and it starts to load
gets to the windows screen the nothing happens. no errors no nothing.
I can still move my mouse around so it is not acting like it is froze.
So im thinking vista alter something when I booted both drives. does
any one know of a fix for this. I really don't want to loose my xp
mse2005. I would like to dual boot them if possible.if not thats fine
I just want to be able to run xp mse2005 again :-(.. thanks for any
help.