Dell mouse triggering double-click on almost every single-click
Solution 1:
Unless this mouse behaves differently on a different computer, I would say that the mouse is bad.
I work for a company that uses Dell almost exclusively, and I can tell you that this is exactly what happens when the mouse starts failing. They begin intermittently processing single clicks as double clicks.
We throw them away when this starts happening.
Solution 2:
I had a Kensington Trackball which was doing the exact same thing. I read a bunch of boards and nothing worked. I threw it away and bought a brand new one. Problem solved! Turns our it was a hardware issue. I have read that other people with the same issue have discovered it is not software based too.