Quote: "I was hoping for someone to tell me that I can install one linux off the usb from the other linux, so that when I reboot it's the new linux. I guess that can't be done?"
Well i was assuming the version you have didn't support your USB thumb-drive. If it does, than of course that's the way to go. Do you have enough room to copy the install. If yes, than does that version have a partion manager as a part of the install.
Linux distro's vary greatly by vender, and by version, so it's impossible for us to tell. For all tense and purposes you could have compiled you own kernel and have a binary file. I'm just not sure what tools you hae available. Do you have a separate partition avail. If so, then i would set it up as dual boot (depending on room) and then wipe-out the old version once you are satisfied with the new version.