Shift key randomly activating.

[Fermosi]

Hello, i m not sure this is the right section to post, some may argue its a hardware-related problem.
Anyways, since a few days my shift key is acting oddly, usually getting stuck, somwtimes activating and deactivating randomly. The keyboard itself is fine, i tried both usb and ps2 keyboards, the problem persists. Its not a sticky keys-related issue before anyone jumps at it.
This odd behaviour still persists after unplugging the keyboard: it can be seen through the on screen keyboard. I tried reinstalling my OS as a last resort but im still getting this. Does anyone have a clue?
Any test i can run to help identify the source of this?

[DaveLembke]

Assuming this is a desktop computer, I have only seen an issue like this once in the 30 years working on computers, but it wasnt just a shift key. In the system I observed which was a 486SX 25Mhz back in 1996, you could start Windows 3.11 and open up word document and then random ascii would show up keyed. Swapping out keyboard didnt fix this, and clean installation of Windows 3.11 didnt fix this. In the end it was a bad keyboard controller chip which meant having to replace the motherboard.

But in your case you have only the shift key, and its doing this from both USB and PS2 and different keyboards, and you too have performed clean installation.

Thinking you too might have a motherboard that is having issues, just odd that its only the shift key, and is happening both with PS2 as well as USB, and that you are not getting a keyboard error at post diagnostics which the 486SX 25Mhz sometimes would display.

What is the specs of this computer, make/model? Some computers were built with faulty capacitors that can cause systems to act strange, and some models are very common to open and find swollen and leaking capacitors.

[Fermosi]

The pc is an assembled one.
Runs on an alive-xfire esata2 mobo (old motherboard lying around, no actual xfire used, i wouldn't REALLY bother changing it if that was the cause)
Posting the rest of the specs in a dxdiag log, which, by the way, made me note something odd : there are a lot of devices apparently connected to my pc. Lots of (non-existant) keyboards and mice. I wonder if that's the source of my problem.

[recovering disk space, attachment deleted by admin]

[Fermosi]

Sorry for the double post, but i figured deleting the keyboard configuration (?) files in the registry and rebooting the system temporarily fix the problem.
The files are specifically : KeyboardClass0, KeyboardClass1, KeyboardClass2 in the Computer:\HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\KeyboardClass directory in the registry.
Though this only fixes my problem for a few hours apparently. How can i work around this?

EDIT: Then again this might just be pure luck, and the files i deleted may have nothing to do with it, it was just the closest thing to a keyboard configuration i could find in the registry.

[BC_Programmer]

Try starting in Safe Mode, and see if the issue persists.

[Fermosi]

Tried safe mode over a 10 hours sample. Nothing apparently, although it doesn't really have a timer : sometimes it bugs out in 5 minutes, sometimes in 2 hours..
Anyways, since it doesn't seem to do anything in safe mode, it should be some kind of external service messing with it, right?
Should i use some diagnostic program to track what's causing it, and in case, what would you suggest using?

[BC_Programmer]

Tried safe mode over a 10 hours sample. Nothing apparently, although it doesn't really have a timer : sometimes it bugs out in 5 minutes, sometimes in 2 hours..
Anyways, since it doesn't seem to do anything in safe mode, it should be some kind of external service messing with it, right?
Should i use some diagnostic program to track what's causing it, and in case, what would you suggest using?

It is a software problem; could be a utility application or another device driver. You could try a tool like Mike Lin's Startup Control Panel or Autoruns, and see if there are unnecessary services and programs you don't need, or try disabling them one by one, rebooting, and seeing if the problem is gone. Obviously that could take some time.

[Fermosi]

Let me get this straight: if i use one of those utilities while the bug is "active", do i HAVE to reboot for the changes to take effect, or the disabled process/service stops functioning immediately?

[BC_Programmer]

Let me get this straight: if i use one of those utilities while the bug is "active", do i HAVE to reboot for the changes to take effect, or the disabled process/service stops functioning immediately?

You would have to reboot for the changes to take effect, yes. You could end processes via Task Manager as well, I suppose. Though be prepared to reboot if you kill one you need.