Since then IE has not been working properly. For instance we can't see anything on YouTube - The screen is black and there are no buttons visible. Gmail will only load in basic HTML format. Also there are bits missing from the websites or not working. From research so far I think these are the Java applets. For example I could not sign up to this forum on the infected computer, because items such as the Are you human? characters were not visible.
I've tried reloading Java several times and reloading Internet Explorer. I've been into Tools, Internet Options, Advanced and done Reset. I downloaded CombiFix which came up with a 7 page report and stopped virtually everything working, which I cured by doing a System Restore to a few days back.
(This is an HP Pavilion g series machine using Windows 7.)
(Any advice on educating teenage boys on how to avoid downloading viruses also appreciated!)
Edited by Andrew, 26 April 2012 - 11:33 AM.
Mod Edit: Moved from internet apps to AII - AA