So, I just got this new PC, with a quad core, 8800 GT graphics card wireless keyboard and mouse, etc. Now, it all runs fine and fast, except for the dumb mouse; the mouse wheel button has to be pushed either towards the very top or bottom of the button for it to middle-click. If I push it down right in the middle of the wheel it doesn't do anything at all. Is it supposed to be like this? Or have I maybe got a dud mouse?