Anyone Play On The Zone??

My client had 2 identical PCs that were completely infested with viruses and spyware etc. I am sure they are now completely clear. The only problem left is that his elderly father regularly plays chess on the internet from one of the computers at http://zone.msn.com/en/chess/default.htm. It now won't work and is causing serious problems in their household as it works perfectly fine on their business machine!! The problem is when clicking on '1. Play with other players', an error message is returned 'Sorry, we were unable to install your game. Follow the instructions below. If you still have difficulties, click here to install again.' None of the Microsoft instructions helped. I can find nothing on google. I tried lowering all security settings, resetting settings and allowing all activex. I switched off the firewall and I tried a different browser to IExplorer. Still the same error message. It would be a lifesaver if anyone could offer some advice and let an old man retire in peace!! )

Thanks!!