Are you using your mouse on a shiny surface? Have encountered completely erratic behavior for some mice that way. Put a piece of paper underneath and see if it stabilizes. Are the drivers completely up to date? Have you tried another port if it's usb? Finally, is it connected usb and ps/2? Try only usb. Those are some of the issues I encounter regularly with wireless.

For anyone who may be interested in an update to my problem... I finally managed to get a Bhutan Telecom engineer to stand by my computer and actually see it disconnect from the internet. He hooked up his own very high-tech looking box to my cables and verified that the problem was theirs, not my modem/router. And from the very next night, I had continuous, 24 hour connection. I rang him to ask what the problem was, and he said that they dug up and replaced the old cable down the road (narrow diameter and many old repair joins). They replaced it with a new, larger diameter cable. So now, I only get a drop-out every couple of hours, and that for only a couple of minutes before it automatically reconnects. A pain when I'm on Skype, but pretty standard here. But he still cannot explain why it used to disconnect punctually at the identical time every night.

The problem is bandwidth. Insufficient bandwidth exists to support everything as wireless. Wireless will be mostly for devices that have low data requirements. Wireless also adds another level of complexity making problems easier and solutions harder. For example, microwave ovens and other devices share same frequencies as wireless applianced. Sometimes a defective microwave leaves the consumer comfused if no hardwired devices also exist. Best solution to wireless problems starts with first learning what is and is not working from hardwired devices. Those are also best deviced to identify a wireless problem. Best wireless solutions mean routing hardwire ports to various areas in a building. Then a wireless problem can be solved even by connecting an Access Point to that existing hardwired port. Just one of so many reasons why hardwire cables will always be required. A refrigerator will best work wireless. But wired port for some devices will always be necessary. Numbers make that obvious. Too many only know by never learning the numbers. Subjective knowledge is always suspect. Better informed consumers install pipes (as another has recommended) so that the few necessary hardwires (current or future technology) can be easily installed.

I suppose there could be an interference problem. I don't know the frequency band that your mouse uses, but did the problem start after you added a piece of electronic gear that uses electromagnetic waves, say a new cell phone, a portable house phone with base station, or a new server for internet use? Maybe a nearby neighbor has added a boost to his modem/server. Perchance do you have blue-tooth equipment running? Check your mouse instructions pamphlet. Does it have a choice of frequencies on which to operate? If so, try changing channels.