Mouse cursor not moving
It would be easier to answer this with some more detail - does the cursor ever move, or does it work for a time at startup, then freeze, and if so, when does it freeze? Does the keyboard work? How about other USB devices? Is the mouse connected to a USB port on the Mac, or does it go through a USB hub? Do you get a pop-up menu if you control-click? Does the mouse work if it is plugged into a different port or computer?
In the absence of such important details, I will have to write a relatively long diagnostic routine.
The very first is to verify that the mouse is powered. If it is a laser mouse, pick it up and look at the bottom. You should see the red light coming out of the hole in the bottom. If you do not, unplug the mouse and plug it into a different USB port on the computer. Do not plug it into the same hub if it is connected through a hub (if the hub is bad, you won't differentiate the problem). If the mouse lights up and the cursor moves, the USB port you were using is not supplying power (if the dead port is on a hub, now you can try another port on the same hub to see if the hub or its power supply is bad). If the mouse does not light up at all, then it most likely has a broken tail (worn out wire in the cable). Unfortunately, first-generation Apple laser mice are relatively difficult to disassemble for service. Try another USB mouse (a generic two-button mouse will work; the right button has the same function as option-click).
If the mouse lights up but the cursor does not move, you may have a broken data wire in the mouse tail, or a system or application hang. Try holding down <Apple>-<option>-<esc> to see if you can get the force-quit dialog. Press the power key (or <control>-<eject> on most Apple keyboards) to see if you get the sleep/restart/shut-down dialog. (Keyboard shortcuts for this dialog: esc = cancel, s=sleep, r=restart, <return>=shutdown.)
A restart may undo the problem, at least temporarily (usually this indicates a software problem). Software problems that actually freeze the computer are relatively rare in the Mac OS, but bad web scripts or poorly written applications can do it. It's a good idea to run Disk Utility after a freeze and forced restart (forced restart: <Apple>-<Ctrl>-<power key>) to make sure the file system is in good order. If it is a software issue and reinstalling doesn't fix it, avoid the software or whatever conflicts with it until a fix is published.
It is also possible that the operating system is corrupted, perhaps as a result of a failing hard drive or a power glitch while saving something to the drive. Check this by putting Disk 1 of your OS installer set in the optical drive and restarting while holding the option key until you see both a hard drive icon and the optical drive icon on the display. You should be able to use the mouse or the arrow keys to select the optical drive (once you start from Installer Disk 1, you can run Disk Utility to try repairs on the hard drive file system). If the mouse works normally when the system is booted from the optical drive, you have a problem with the hard drive OS.
The worst case cause is a hardware issue. This could be a damaged USB connector on the computer (it can be replaced, but generally requires a high level of skill to remove the bad connector from a multi-layer circuit board without wrecking the board, and for Macs less than ten years old, lead-free solder is required). A memory defect could cause a system hang, as could a fault on the logic board, or even in the power supply. These often appear to cause the mouse to freeze randomly and may display a temperature sensitivity (the computer works for a while, then locks up when it gets warm; neither the mouse nor the keyboard respond). If you suspect a memory issue, try removing all but one memory module. If the computer works normally (other than running slow or other signs of inadequate memoroy), then add modules back one at a time until the computer fails again. (CAUTION: only handle memory modules by the edges; they are easily damaged by static electricity. ALWAYS turn off the computer and unplug it before removing or installing a memory module; installing a module with power on can do serious damage to the module or logic board.) If the computer fails with just one module installed, remove it and try a different one. If it fails with any memory configuration and after all the previous tests have been run, you may have a defective logic board, power supply or USB connector board (if separate from the logic board).
Jul 08, 2013 |