Mouse wheel causing PC to shut down apps and windows

I think the title explains pretty well, but when I press the middle mouse button (Press, not scroll.) it shuts down whatever is up, including taking me to the Standby/Shutdown/Restart option. I have a USB LapMate optical mouse and I run a homebuilt PC on Windows XP. Help?

 

Did you install drivers for the mouse? They sometimes stupidly auto set the button to close app. It'll often appear in the icon bar thingy at the bottom and usually looks like a mouse.

Open the full bar and mouse over each until you find the icon. Failing that, try mouse properties in the control panel.

 

No, we didn't have any drivers to install.

 

Traixx2 is correct go to control panel click mouse and you should be able to customize any setting for the mouse buttons you have.
If that doesn't work contact their support department support@asiapac.com.sg and explain what problems you are having you may have a defective mouse.

 

Well, I logged on a day after and it's stopped. For now.