There is no common cause or cure for this one. But I will share I often cure this on laptops by disabling the touch pad. It's almost a magical setting to some but worth a try.
Next I often uninstall or remove any and all MOUSE DRIVERS. I let Microsoft's Windows supply the mouse driver and that simplifies the picture since many mice software can autoclick as some feature in the software provided. Since many don't want to dive into said software its best we just remove it.
Here is the problem: The mouse seems to have a mind of its own. If the pointer is placed anywhere near a hot spot on a webpage, near a command box, etc. it will open/close/etc. just by hovering over the area that should be clicked.
I have a Dell Inspiron 1720 laptop, running Vista Home. 4 GB RAM (but using 3.5 thanks to 32 bit) and I regularly run McAfee Security (updated automatically.) Trying to fix the problem, I ahve installed Malwarebytes Anti-malware software and had a clean run with it...and have run TuneUp2009 with no major issues (a few minor related to internal home network, but nothing to cause my problems.) I even ran the several hour long DELL diagnostics and the mouse and pointer checked out fine.
I did have one bad sector, and am wondering if that is the root of my problems? I uninstalled drivers and reinstalled for both mice that I am using (Microsoft Wireless Optical Notebook 4000 and Logitech LX3 wired optical mouse.) The problem actually seems worse after the reinstall. It is making the computer almost unusable.
Anyone experienced this? I don't think it is a hardware issue with the mice, since two different mice are doing the same thing in all three USB ports on the computer. Any suggestions are appreciated. My husband generally handles these things for me and he is out of the country on business. Naturally...