Dual boot problem

Hi -

I have just redone my dual boot (XP/Vista) system and have encountered a problem. I installed XP 1st, then Vista (each on it's own hard disc). Since I installed Vista I can no longer boot into XP. It loads the initial XP logo screen, then blue screens with 'inaccessible boot device'. I think Vista has reassigned the drive letter of the XP disc, but it won't let me change it back in Disk Manager as it says it's a boot volume. How can I correct this?

Thanks for any advice.

similar problem in:-

http://forums.hexus.net/operating-sy...any-ideas.html