Dual Boot Drive Letter Assignment

[BillHicksRIP]

Due to a bt of a disaster yesterday I've had to rebuild my XP and W2K3 Server dual-booted rig. I installed XP on it's own partition first, then installed W2K3 on the other partition. I'm working on the W2K3 image at the moment and have noticed it's installed Windows into the H: drive. The XP image is showing as holding the C: drive. Can I just change the letter assignment within Disk Management or will that screw things up? What a nightmare this has been!

 

[BillHicksRIP]

Aw crud. I'm not sure where I've gone wrong here. I've had a dual-boot of Xp first followed by W2K3 working fine for months, but on the rebuild it all goes west. So if I attempt to re-install W2K3 is there any way to ensure it installs to C: ?