I am currently running Windows 7 Home Premium 64-bit with an AMD phenom x2 550 processor. The problem I am having is new since upgrading to Windows 7, but I have read similar bug reports from XP users.
The best description I can afford of the problem is that, at seemingly random points of time, my Logtiech G5 mouse will start to fail to register clicking. The problem becomes strange as sometimes it manifests in only specific open windows, or on the taskbar, yet allows right clicking to open a menu and left clicking to function in that menu.
The common denominator between my problem and several of the similar problems I have read of is that CTRL-ALT-DELing to bring up task manager temporarily fixes the issue.
A few other things to note: For me, the problem usually start occurring while I am playing World of Warcraft (I play in windowed mode if it matters). This may simply be a coincidence though as I play it frequently. The problem presents itself in the game as seemingly the left click getting stuck or clicking at an uninhibited high rate because holding left click ingame allows rotation of the camera, and when the problem occurs my camera will rotate without me having to left click at all.
I have yet to find a solution for this problem that involves definite understanding of its cause. The solutions I have read have included uninstalling Anti-Virus software and installing Logitech Drivers in compatibility mode. Neither of these solutions has worked for me.
Currently trying again to remove any Logitech drivers I trying the plugandplay drivers.
More about :logitech intermittently fails register clicks
I had similar troubles when using a wireless KB and a diffrent Wireless mouse
I discovered windows had installed drivers for the USB and PS2 port and had some labeled as hid compliant. I had to go to Device mgr. under mouse and disable each one until mouse stopped working(enabled that one and disabled the others)
did the same for keyboard.
What is device manager showing you?