System you are using. That advice is given right in front of you when to decide to make a new message.

If it is Win XP that you are trying to move, that'll likely explain it. XP doesn't transfer very happily, and then don't be shocked if Norton manages to make things worse.

You may be in for a new install.

If it is XP and you get it working, you will be able tho change the drive letters to anything that you want, as long as you change all the paths for programs, shortcuts that point to the drive.