Do you mean when it starts up and you see both os's and change the names of them?
If so I don't think it's possible, I could be wrong but if anything it should be in the MSCONFIG, I've had a look at it's not letting me change mine so I highly doubt you can.
Hint to open an elevated command prompt as indicated in the instructions: in Vista/Win7 - Start>Run>CMD but hit ctrl-shift-enter (instead of just enter). In WinXP as long as the user is an admin, then the command prompt is automatically elevated.