Here's the short answer for those who like to get to the point:

Open it up and put some layers of tape (or cut up a post-it note) on the button that pushed down on the switch.  The distance between the switch and plastic button are now shorter and makes a more firm click which seems to fix the double clicking (at least for me).

Long version:

I spent $39.99 for the Alienware Tactx Mouse a few years ago from "Dell days of deals". Awesome deal at the time but didn't expect it to fail so soon. I had a problem with it double clicking randomly whenever I did a single click. It was frustrating during game play and using the windows 7 desktop. I checked my windows 7 setting to ensure all my mouse settings were fine and even tweaked the double click sensitivity in the settings but it didn't help.

I googled for solutions but all I found was:

1) people had a hard time trying to get Dell to fix it or it wasn't under warranty anymore.
2) there was a failing switch because it was made in china.
3) open it up and clean it up and it might help

I decided to open it up and see if a little clean up and poking around could fix it. If that didn't work, I thought about physically swapping the left and right clicker switches on the board but if I mess that up then I'd have to toss it. So that option was my last resort.

Step 1: Remove screws.

There are 5 screws. Use a blade and peel back the mouse feet slowly until the screws are revealed. You do not need to remove the feet completely otherwise it's hard to put back on so that it's smooth. If you have taken off the feet completely then you'll probably have to clean up the glue and re-apply new glue such as rubber cement to make it nice again.

Step 2: Cut up some tape into small bits and start stacking them above the microswitch button. This will make the distance you click shorter and will provide a more firm click. This should resolve the double click issue.

Protip: Since you have your mouse apart, use some compressed air to clean up the dust inside.  You will find big dust balls around the wheel area which will affect scrolling.

Step 3:  Reassemble the mouse and screw in the screws. The feet are probably mangled but old glue should still hold it. Otherwise clean it up and add some new glue should keep it in place.

I hope this helps someone out there. It's not too difficult to do and worth a shot. I've read too many messages of people throwing out this mouse because of the double click issue.