Here's some things that may help with your mouse woes. Start with the basics:
1. Make sure the mouse is clean and you have a good connection.
2. Play with the speed setting a bit. Set the double-click speed to medium. If you set the double-click speed to it's highest, it feels like it's not working. I've had this happen at work before.
3. If that still doesn't work, and you have access to another computer, plug your mouse into it. If your mouse acts fine on another computer yet acts up on your machine, the issue is with your computer. If it does the same thing on another machine that it does on yours, the problem is with the mouse.
3. Run anti-spyware programs to make sure you don't have any spyware. Often things that feel like small, annoying glitches like this are the result of spware messing something up.
I reccomend SpywareBlaster v. 3.3, Ad-Aware SE personal, and Spybot Search & Destroy 1.3. They are all free, easy to use and get rid of most of the stuff out there. You can find them all here:
http://www.spychecker.com/topdownloads.html Once you have the programs installed, update them so you have the latest protection.
4.Also, run your antivirus software and make sure you don't have any viruses.If you don't have an antivirus program, you can get one here:
http://free.grisoft.com/freeweb.php/doc/2/ Avg is a free antivirus program. Again, udate it to make sure you have the latest protection.
After installing and updating your antispyware/antivirus software, scan the computer for spyware and viruses in Safe-Mode.
5. If it's still not working, go buy an el-cheapo mouse you should be able to find one for 5-10 bucks. Plug it in and see if it works. Don't get an expensive new laser mouse until you're sure your old one is dead. By buying a cheap one, then the one you want later, you not only have a spare, but you'll be able to know if your mouse is shot without spending much money.
Hope this helps guys. If not, let me know.