Menu pops up when I click left-hand mouse button

Hi, whenever I press the left mouse button on my laptop a menu pops up as if I have clicked the right-hand mouse button. The right-hand mouse button functions normally (with the menu popping up). Any idea what's wrong? Do I have a virus?

Any help much appreciated.

[centaur]

You should be able to get into the Touchpad/mouse control via the Control panel. Once there, check to see if you can swap for a left hand or right handed operation and try setting each in turn to see if it changes the way the buttons behave.

Thanks. Sorry not to reply earlier. I tried this and the lef-hand mouse button functions as before but the right-hand one now just operates with no menu. Seems like there must be something wrong with the left-hand button -- either hardware or software. I don't know which.

[CaNsA]

try tapping both buttons at the same time in quick succession.

This has worked for me in the past, usually the sign of a mouse about to die.