Mouse disconnects when clicking both mouse buttons simultaneously?

[Techhog]

I was trying to play BF3, but I can't because if i try to click the left mouse button while holding the right button, Windows makes a sound and I can't shoot. -_- I swear this OS is intended to kill PC gaming. How do I fix this? What stupid pseudo-gesture is MS forcing here?

EDIT: Nevermind, it's the mouse. E-Blue Cobra Junior. Any way to fix this?

EDIT2: Changing the DPI fixes it... Weird.