Check the Logitech Forum
and you'll see that you are not alone. Several solutions are discussed there, but different ones seem to work for different users.
Personally, I have had much difficulty at times but the 4.x versions run OK for me now. Also, make sure to give UberOptions
a try. UberOptions is an add-on that gives you a lot more options, more customization of the various buttons on different mice. (meeces?) E.g., on my MX Revolution wireless mouse you cannot use the middle button in Firefox to open a new tab. UberOptions adds that plus many other added features. UberOptions is developed by Richard Lowens - rloens on the forum. He's a user who is apparently a good coder also.
Setpoint used to automatically install the Logitech Desktop Manager (LDM) which you don't want. Part of it is simply an installation of Backweb. It is constantly running in the background and sends advertising pop-ups to your desktop. (I think they were all Logitech ads, but I hate it just the same!) It also pops up when a new version is available, but you can get that functionality with Secunia's free PSI program. (Personal Software Inspector
) It places 78 separate entries in your Startup config! It also talks to Logitech far too much for my liking.
Also, if you use a Logitech Web Cam, be very careful and read up as much as you can before installing the drivers for it. Two separate webcam drivers turned out to be incompatible with Creative SoundBlaster sound cards and caused some sudden hard crashes - hard to recover from because as soon as you'd restart your PC it would crash again as the sound card drivers initialized. I had to use system restore in safe mode. After the first time this occurred on a pretty widespread basis Logitech discovered that it was their built-in sound drivers for the webcam's auto-record audio feature - Echo-something or other. Then after getting that fixed they released another driver with the exact same conflict 8 months later!