Mouse wont right click since SP2

Hey,

I never had any trouble with vista so far, untill I installed SP2. (Vista home premium x64)
Since I installed SP my (USB) mouse wont work properly. About 50% of my right clicks wont work. Sometimes it works a couple times in a row, than it doesnt for a couple times, really weird. It's worse when i try to play a game than on the desktop or in firefox/IE.
Does anyone have a similar problem or could anyone help me fix this?

I've allready tried several solutions I found online, such as uninstall drivers and reboot and disabling shell extensions.

Thank you in advance for your reply.

Does it use a battery? Try a new one just to eliminate that possibility.

Its a basic usb mouse with a cable.