ThinkPoint virus

We have Norton Security Suite downloaded from Comcast.  This afternoon, one of my children was online and downloaded and authorized a malware program, entitled ThinkPoint, to the computer.  It prevents you from getting back to your desktop when you try to re-boot.  After researching it, I learned that it apparently prompts you for a credit card # to purchase software, although I did not see that particular screen.  I was able eventually get back to the desktop and run a Norton scan.  Unfortunately, Norton did not remove the virus.  I had to get a different anti-malware software program to eventually get rid of it.  I cannot find any help on the Symantec site for this problem.