Please, please, we beg you, don’t do it! Even if it seems logical, like it’s the right thing to do, we urge you not to change the boot/primary drive, or otherwise disconnect other drives when installing another OS!
Seriously, we had no idea so many people engaged in this activity until EasyBCD started spreading like wild fire. Here’s a fact for you: 95% of all support requests for EasyBCD in our forums come as a direct result of users disconnecting their Windows Vista/XP drive before installing Linux, Vista, BSD, OS X, Windows 2000, XP, etc. It’s one thing to reinstall the bootloader when you’re done, and quite another to have to recreate the required boot files to make them point the right drive/partition combo.