There are number of harmful programs on the Internet increasing at alarming rate, and you using some Anti-Virus protection but it was not really Kicking the big guns like Spyware, Adware, etc.
The freeware "Amust 1-Defender" offers you a much needed protective shield. Download "Amust". After Installing the Software the program recognizes the browser and default mail program and creates new shortcuts for them, which are available in the "Amust 1-Defender" program window. The tool thus starts the respective programs in its "Safe internet" mode with restricted user rights, similar to security measures in Windows Vista that prevent unnoticed installations. To configure the program's options, open the applicable settings in "Amust 1-Defender Configuration". Active the "Alt" option here to define this key as an option to skip, and exit the dialog box with "Ok".
Note : Internet Explorer must be set up as default browser. Make the necessary changes on restarting the browser.