Drop-Down Menus Won't Stay Open

I have a weird problem on my PC in that on many (but not all) drop-down menus, when I click the arrow to drop a menu it drops but then immediately closes again before I can even get my mouse moving into the options available - and this happens repeatedly. I may be able to get it to open once in every five or six attempts if I am lucky. This is mainly on dialogue boxes where most drop-down menus are found although not all. For example Word dialogues I have no problems at all.

I've done some searching around and found details of the MS System File Checker and done a scan. This seemingly found corrupt files and repaired them AND produced a 12.5MB log file. However, I still have the problem.

More searching found it could be due to multiple mice found in Device Manager (DM). Looking in my DM I found six entries under Human Interface Devices labelled "HID-compliant device" with no explanation of what they relate to. As far as I am aware I should not expect to find any more two at most, these being a mouse (Logitech optical mouse) and a Wacom Bamboo tablet. I uninstalled the tablet leaving just the mouse and rebooted but I still have five such entries. I also have two unexplained entries under "Mice and other pointing devices" labelled "USB Input Device" - a third such entry is labelled "USB Input Device (Logitech Download Assistant)"

Whilst my tablet was uninstalled and indeed disconnected, I did some further checks using just the mouse. Unfortunately it doesn't seem to make any difference - I still cannot guarantee that a drop-down box will remain open. However, I have noticed that it does not seem to affect the drive drop-down. Only the filename and file type drop-downs - at least in saving and opening dialogues but I'm sure I've had other drop-down menu types where this has also happened.

My first question therefore is: is it safe to remove the excess HID device entries in my DM and do I have to boot into Safe Mode to do it?

PS I should add that my mouse has a switch on it enabling me to switch it off when not in use. It is therefore switched off most of the time. Also, prior to reinstalling Windows 7 on 12 October I didn't have this problem and I had exactly the same system hardware config and the same software installed.