How do I stop my Drive letters changing across Operating Systems?

I'm currently running Windows Vista (Home Premium) and Windows 7 (Ultimate, build 7000). I have split my laptop hard drive leaving my Vista Partition, and creating a new one for Windows 7. I have installed Win7 all well and good, however when I use Vista my vista partition appears as Drive C: and the Seven Drive D:. Whereas under Win7, the Windows 7 System Drive is given the letter C: and Vista (which was previously unassigned; hence I assigned it random V:).



How can I make it so they keep the same drive letter association across both OS's? I would like Vista to be drive C: and Seven to be (well frankly anything else within reason) as long as it's consistent.



Any ideas?

Cheers,

DeanHow do I stop my Drive letters changing across Operating Systems?
the primary hard drive of your computer is always labeled c



although you can change this, it is not suggested as it will invalidate all references to to the C drive, including those that are made by your operating system