This tells you how to do it under xp (and vista), click here.
But note the warning;
"1. You should not change drives containing system information or installed programs."
If you haven't installed any software (other than the os), then there may not be any probs.
There should be a way to do it, in a non-destructive way, from within PM 8, unfortunetly, it's been many years since I last used it.
The same Q was asked on google answers, you may find it helps, click here