I bought an MX1000 mouse last week which is now driving me around the bend. All I can get HL2 to recognise (and work) are the left and right buttons (which I use for primary fire and jump). I have always used the middle button press for secondary fire (HL2 recognises this as mouse 3 in the menu, but won't use it in game). The game will also not recognise any of the side buttons, or the side-rocking feature of the scroll wheel. I'm on the verge of taking the mouse back and getting a refund unless anyone can suggest where I'm going wrong.