Okay, I've heard that windows upgrade can be a little fussy when it comes to multi-boot issues.
I currently have a triple-boot setup, XP64, Vista Business 64 and Win 7 Home Premium 64. Each OS is on it's own separate HDD. I now have an upgrade disc that will give me Win7 Pro 64.
My question for you guys is, will the upgrade keep my boot setup intact? I don't want to risk having to reinstall the other two OS's because the upgrade wipes the boot sector or something.
i don't think and upgrade would mess with your bootloader...not much excepth changing the name. and in case it does ruin the bootloader, use BCD editor or something like that to restore entries for xp and vista. i don't understand why you need three versions of windows though!