Permanent "Removable Drive" Letter?

I've been searching around all over the place yet can't figure out how to do this, or if it's even possible. I just bought a new 120GB WD Passport external HD, and I plan on installing a few programs on it that are "root" dependent, as in it will search for the files under the "F:/---/---" directory. Issue with this though, is that letter will change anytime I plug it into another computer, or even if I plug it in after I plug in a flash drive.

What I'm wondering is, is it possible in Vista to assign the drive a permanent letter, such as M:/ so that it will always appear as that whenever I connect it? I wouldn't mind if either only my laptop will recognize it as such by reserving that space, or making the hard drive always set itself to that letter on any computer (If that's possible). I've tried checking the preferences on the drive, but there's no option to reserve the drive letter like there is on any normal other drive. Any help will be greatly appreciated.

 

You can right click on "My Computer" ->Manage-> Disk Management ->Highlight drive and then right click and select "Change Drive Letter/Paths". I never installed programs to a portable HD; however and I use CD-Drive/DVD-ROM emulators with multiple external hard drives (4) so the drive letters are always changing.

 

Yeah, I actually just figured that out before I read your post and it seems to work for my laptop. Thanks for letting me know though. I assume that you can't make it that letter permanently for any computer you plug it in, but so long as I just do that when I plug it into a new computer, I should be fine. Wait, if I was to plug it into a computer while using a guest account, could I still assign it a drive letter, or would that privilege be only reserved for Admins? I don't have much experience using guest accounts.