First, check in your control panel for " Mouse" and check that everything is set right and run a quick diagnostic. If you're still having trouble, the best thing to do is just buy a new wireless mouse for it. They're pretty cheap, easy to set up and you don't have a wire around all the time. You can get a decent Microsoft wireless mouse for around $10.00
Two more suggestions that Rooster did not mention are:
1. Try another mouse before you run out and purchase one. If the exact same problem, it might be the USB port also. The port can be tested further by plugging in known good USB devices and see if any of them work. USB devices I have discovered have a tendency to have problems especially if you have cords on them AND you have cats. BAD combination, but I love the beasties so I deal with their cord fetish.
2. Try plugging into other USB ports and see if it works. This will also force a re-download from the USB device of the appropriate driver.
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