dragged

Hi, I am through 2 logitech (sub 500Rs) mouse in 3 years. need a better mouse(wire/less) for light gaming,surfing,photoshop,Autocad ... They tend to double click when single clicked... loose a click when dragged etc. need a scroll mouse nothing too fancy. Budget 500 to 1000. Please give...

In my systems, when I click an xpi file, that is a Fire Fox extension, Firefox opens but nothing happens. I tried to open the extension window, and dragged xpi file there, still the extension does not get installed. What may be the treason?