How do I revive files off a hard drive..

..when the Master Boot record was erased by a virus. I was able to go in using Norton unearse and undelete a few directorys. What I didn’t know was, when I closed the program I wouldn’t be able to go back into the program and unerase files from directories I had restored. Any thoughts? I have permission to take the drive somewhere or fix it myself. Are there companies that will be able to get in to the drive and get the info off?

Bryan