I've tackled a few of these infections before and they've always been easy to resolve - hopefully it'll be the same in your case:
Tell the young kid that he or she first needs to start the laptop in Windows 7's Safe Mode. Hopefully the laptop will bootup fine and that pesky FBI message won't appear. If so, the next step is to run System Restore and choose a date on the calendar when the laptop was running fine.
When the System Restore completes the laptop will restart normally. If everything looks fine then the last thing to do is to run an anti-malware scan to mop-up any (inactive) malware files that might remain. The free version of Malwarebytes Anti-Malware is suitable for this job and is highly effective.
Lastly, get the kid to renew his Norton subscription or install another anti-virus program ASAP.