Perhaps this thread belongs in the Windows Forum.

Windows XP, Home Edition with Service Pack 2

About once per week, my Mouse acts as though I am using Shift-Left Click.

I Click on something and a dozen or more items are selected.

When it happens, I turn the system off and restart it. This works, but I wonder what causes the problem.

Is there a way to make it go away without shutting down?

Probably just a sticky shift key. Spilled anything on the KB lately? :p How long since you last used a can of compressed air to blow out the KB?

Seems like a pretty specific condition, Dinosaur. That it is so intermittent, there no other sticky keys, and it goes away after rebooting, lead me to think that this is mouse driver related. Is this a PS2 mouse, or USB? Are you using the default Windows mouse drivers, or third party software? Does it usually seem to happen about the time you're doing anything in particular? Things like using another usb device, running certain programs, anything like that?

Pangea33: Your thoughts about mouse drivers might be pertinent, since I am using generic XP drivers instead fo the drivers which came with my pointing devices (Those are not compatible with XP).

It seems strange that the problem started about a month or so ago. I have had the system for about 18 months. It might be due to some recently installed software. I have over 70 applications installed on this system. I only use about 15 regularly.

The problem is so intermittent that I cannot associate it with any particular scenario.

I intend to download device drivers for the mouse and the trackball. I use both since I sometimes teach senior citizens to use a computer and/or help them purchase one. Many have problems with a mouse, so I let them try a heavy trackball.

BTW: If you know anybody who has trouble using a mouse, suggest a heavy trackball. Some people tend to move the mouse when they click a button, especially when trying to size a window. A heavy trackball allows them to position the cursor and then lift their thumb or finger from the ball before clicking.

So, does the mouse use a PS2 or USB connection? If it's USB, and you're using the default XP drivers (like I do), I recommend you try one of those simple convertors to connect it to the PS2 port. For my system, I never experience problems through the dedicated mouse port. Something I can't say is true when using the USB interface.

Pangea33: I just installed the latest drivers from Microsoft, and will see how the Mouse functions in the next few days. My Mouse & Trackball are so old, that they are not specifically mentioned by the Microsoft site or the list provided when I installed the driver, but they seem to work okay.

When I have time to tinker, I will try putting the Mouse on the PS2 Port. I have a USB to PS2 adapter. It might be an interesting test of the driver. I wonder if it will run the Mouse via the PS2 Port and the Trackball via a USB Port. Both work okay from USB Ports. The driver pays attention to the one I use.

Windows probably *should* be smart enough to determine which USB input device is being used, but I wouldn't put a lot of faith in that. Especially when those devices stop working properly. Have your ever tried unplugging the unused device when your machine acts up? It certainly wouldn't hurt to try it once.

Pangea33: This is the third or fourth system I had with two pointing devices: A Mouse & a Track Ball. For earlier systems I used two serial Ports. For this & my previous system, I used two USB ports.

My understanding of Drivers & the OS suggests that there might be a problem if I try to use both pointing devices simultaneously. However, if one is just sitting there, and I move or click the other, the OS passes the interrupt to the driver, which does his thing. I have always used devices which function from the same driver.

I think that with some effort, you could use two fundamentally different devices. It would require assignment of two interrupts, one for each driver/Port combination. The second driver installed might even be smart enough to pick an unused interrupt. I have avoided this complication. Currently I have two Microsoft devices which use the same driver. Previously, I had two Logitech devices.

My understanding of Drivers & the OS suggests that there might be a problem if I try to use both pointing devices simultaneously. However, if one is just sitting there, and I move or click the other, the OS passes the interrupt to the driver, which does his thing.
Keep in mind that I am not very educated on this subject, so I am just playing Devil's Advocate using nothing more than speculation. What sort of behavior might occur if both devices went active at the same time? Possibly a misinterpretation of events such as left button clicks? Occasionally my mouse pointer will creep very slightly on my screen without user input. I suspect this is due to using an optical device, on a desktop without a great deal of markings to aid in tracking.

If that happened while I was using a trackball, I can see where it might cause trouble. Perhaps calibrating the devices might minimize erratic tracking, but I don't really know about that. If the devices themselves are causing the OS to get confused, perhaps a simple KVM switch connected only to the mouse and trackball, might help resolve the problem by isolating them.

Mouse drivers are probably the most generic drivers of all. Having more than one pointing device should also not be problematic.

Are you sure you are not somehow turning-on "sticky keys" by mistake. Repeated presses of the shift key is the default way of turning sticky keys on and off but have a look at the settings under Accessibility options.

Othewise see if the problem persists with a replacement or swapped keyboard.

If this were truly the result of a sticky shift key, either physically or through accessibilty settings, then everything you type would be in CAPS. Which you would notice. Enabling Windows Sticky Keys sounds a beep too.

Since this only happens with your mouse, maybe you should see if the problem returns after using a temporary replacement mouse for a while. While mice typically have a long lifespan, this does not mean that one can't develop problems after 18 months. Do you travel with this mouse and throw it around? Is a recent power surge a possible culprit?

Mouse drivers are probably the most generic drivers of all. Having more than one pointing device should also not be problematic.
Agreed. I have had a wireless optical, a USB trackball on a laptop with a touch pad all at the same time without any problems.

I also agree that USB mice tend to be a little flaky at times.

It has not happened since I installed downloaded drivers from Microsoft, replacing the Windows XP generic drivers.

Post hoc ergo proctor hoc is not really logicaly, but sometimes it is true.

Seems strange that the generic drivers worked okay for about a year. Perhaps some interaction with a newly installed application caused the problem.

Maybe it will come back in a week or so.