If your mouse cursor or pointer moves by itself on the screen or shakes, the following may be happening:
* First, try plugging another mouse into that computer… this way you’ll notice if the problem is with the mouse itself, or with the computer itself. With this you can rule out many of the solutions that we give below.
* Beware of optical mouse and reflecting surfaces. Resting the mouse on glass or shiny or reflective surfaces may cause it to malfunction and «move on its own». Even direct sunlight on the mouse can affect it. If you’re using an optical mouse, you shouldn’t use it on a surface that reflects light or slips, it should be a completely opaque surface. As for the trackball mouse, you should not use it on a slippery surface.
* If it is a battery-powered mouse (that is, wireless), check that the batteries are new, recharge them or change them.
* Mouse cleaning: It may be happening that the mouse is very dirty. If it is a ball mouse, I suggest you open it and carefully clean the internal wheels and ball with a damp swab. You may get a lot of lint and it may even be so stuck that you have to use something harder to remove it.
If it’s an optical (light-using) mouse, I’d suggest properly cleaning the light output, also using a slightly moistened cotton swab.
* The connection to the computer may be failing, check that the mouse is firmly connected to the port it is using, especially if it is a PS2 port.
It may also be that the mouse cable is in poor condition. Check especially the portion of the cable coming out of the mouse and the portion of the cable going into the computer. It must be firm and the internal wires of the main cable must not be visible. There should also be no noticeable bruising or «stepped» areas of the cable.
To find out if it’s the computer’s port that’s the problem, find another mouse that you know is working fine and plug it in. If it shakes, the problem may be with the computer and NOT with the mouse.
– OTHER SOLUTIONS:
* Check mouse settings in Control Panel. There you can choose the mouse drag speed, I suggest lowering it a bit; maybe your mouse is not accurate enough for high speed.
* Reinstall the mouse drivers. If it is a generic mouse, it is installed by Windows. But if it’s a brand name mouse, you’ll need to install the software and drivers for THAT specific mouse.
* On the other hand, many times letting Windows take care of finding the appropriate driver also solves the problem. To do this you go to Device Manager (in Win XP: Control Panel – System – Hardware tab) and look for the mouse in the list and uninstall it. Then restart the computer to reinstall it.
* I recommend scanning the computer with an antivirus installed on your computer, also with an online antivirus (see: Online Antivirus) and with some antispyware (see: Free Antispyware). You should do this with Windows in Safe (Safe) Mode, as it is easier to remove malware this way. For this see: Enter Windows in Safe Mode.