Have you tried not using the Logitech drivers, just the one that are part of the OS?
I used to install all the keyboard and mouse drives and software (like Microsoft IntelliPoint and IntelliType that came with the hardware), but i did no better than the original drives that are part of Windows.
The only difference was I can't program special buttons, like a side button to be double click, but I think the generic drivers can do that now.
Go into Control Panel, and try to rest the drivers to the original ones installed during set up. See if you can, and if they work.