Sorry, try one of mirrors on this page :
http://www.majorgeeks.com/Win7codecs_d5959.html
For scan, it's Windows problem, if codec fail, you'll have to reinstall Windows for full functionality.. Or, maybe you can fix inside Windows.
Go to Start > Run > type CMD and press Enter. In Command Prompt type next command :
sfc /scannow /purgecache
If computer ask you for Windows CD, just insert it. This is probably the problem occurred during the removal of viruses.