Strangely I have been getting same/similar behaviour. Sometimes the USB mouse just switches off and require reconnection which is the least problematic. I already have removed the green PS/2 adaptor and have it connected to the main USB port.
The worst behaviour is when the mouse cursor starts drifting all over the place and can't be fixed.
I see quite a few XP/mouse stuff like this via google and wonder if its the new drivers. I have downloaded the latest and will try that but have also hunted down older ones that are still floating around if you hunt them out. 5.2 disc I still have, but 6.1 is on the net via softpedia and 7.1 is the only one now showing at Microsoft.
What kind of mice are you using? I thought that the point of USB mice was so you didn't need batteries (draws power through USB port). As trendski said, uninstall your current drivers and go get the most recent ones.
It's strange though, because I've never had to install drivers for my Microsoft Optical USB Mouse.
I seemed to have solved it after discovering that my USB hub had dislodged its dc power supply cable. I reconnected it and have offloaded as much as possible of my USB onto it as is practical, though the mouse is now running off a Pluscom PCMCIA CArdbus USB 2.0 4Port card.
Haven't had a problem since then, so I reckon power consumption and the lack of available USB power was at the heart of the mouse funniness (mouseyness)
My Inspiron is attached so many more devices now than when I got it
My MS USB mouse stopped working on my inspiron. Batteries are good and i have pressed connect.
It worked when I first bought the computer
I read your thread and did everything you did and more..much more! I was about to give up for the night when I discovered one
telling fact. The computer lied. It said that the mouse battery's was good.
It lied! Thankfully, my Windows 7 has a program which detects
the true nature of the power source and was able to tell me that I needed to put in a fresh new battery in my usb mouse. Simple, yet beautiful, huh?
The second I replaced the AA battery my mouse worked like new!
So before you go all problematic, change your mouse's battery and see if it helps.