There is always a chance you have a bad download.
Do you know anyone else that has an Upgrade DVD of your version?
Did you copy your files to a place they are still accessible?
What software and version were you trying to upgrade from and to?
If you can, get the place you bought the software to send you a DVD.
If you end up not being able to do the in upgrade install, if you do a Custom Install, you old files are still there, but you will have to reload your programs and use the archive to recover your old data.
During the install, you don't have to touch it after the initial setup questions until it is completed. If it stopped and asked you to reboot, then it was showing problems. Do you have anything plugged into the laptop, like USB devices or any other cards you could remove?