Unable to click on taskbar -

Okay, for the last few weeks I've been having this annoying problem. I am frequently not able to do actions in other windows than the one I have open.

For example if I am running IE I can type and click properly in that window, but I am not able to say click the task bar or pop up the start menu. When this happens I can still get the start menu to pop up but I can't acually click on anything to start up with it. Using the keyboard does however work. It doesn't seem to have anything to do with the mouse.

Sometimes even the window I have open sort of freezes up like the task bar and games usually leave me with being able to move the mouse but not being able to click or use the keyboard.

I don't know what caused this, but simply pressing 'ctrl+alt+delete' solves the problem for a minute, but is frustrating to do when you have to do it frequently.

Any ideas what could have caused this?

I'm running Vista and have AVG