Left mouse click brings up right-click context menu continually

This is definitely a head scratcher.
Since the problem exists no matter which mouse you use, and because it happens at random times, I'm thinking that something computer related (either hardware or software) is affecting the mouse button functions. Here are a couple of troubleshooting tutorials that might help. The first (Clean Startup) might indicate if an installed application or service is interfering in some way. The second tutorial is a long list of troubleshooting suggestions. Not every one will apply to you.

Troubleshoot Application Conflicts by Performing a Clean Startup - Windows 7 Help Forums

Troubleshooting Steps for Windows 7 - Windows 7 Help Forums

My hard drive is about 6 years old. I do occassionally backup my files onto anothe drive.

I replaced the Logitech mouse with another mouse and everything has been working so far over the past few weeks. I believe the problem is coming from the USB extentions that I am using and this is what is causing all of the problems. Thank you all for your help!!!

Sweet. Here's hoping you've found a permanent fix. Thanks for posting back.

Thanks!!!!

Replacing the mouse will usually work for about 2 or 3 months and then the problem will return again.

I'm having the exact same problem. I even changed my mouse twice, the second new mouse worked for a couple of months and now the misfiring is back. Since it has happened with three mouses, I'm also thinking the USB port is the problem. I tried switching to a new port just today, but it didn't work.

I had exact same mouse with same problem, I dont think its a software issue as it started all of sudden and looks like its a hardware issue and replaced mouse.