Are you downloading an ISO file? If so, you can write it to USB flash stick to boot and install Windows 7: Windows 7 USB/DVD Download Tool
You can also run Setup file (if you are downloading files or extract ISO to Vista) to overwrite Vista by running a Custom install.
I believe Ultimate Steal (student deal?) is full version, so you needn't worry about qualifying Vista OS. If an Upgrade version, the installer when booted or run will only look for another OS to allow Upgrade version key.
To avoid ever having to reinstall either OS, make a Windows 7 backup Image stored externally so you can reimage the HD or a replacement in 15 minutes.
You can only install on one machine per license. During activation you will make a robocall that trades numbers to deactivate the old install while activating the new one.