The other suggestion was to bring up the On-Screen Keyboard and click once on each of its two Shift keys. That is, I always used the left-side Shift key, so now I used the right-shift key one time. One suggestion was just to use the other shift key once. Two other suggestions offered simple solutions. But trying again with the USB keyboard, with or without the PS/2 keyboard, after reboots, did not seem to fix the problem.

That seemed possible I had recently plugged in a USB keyboard because my PS/2 keyboard was not responding during a reboot with a certain kind of boot disk. The concept here seemed to be that Caps Lock was on when an external or alternate keyboard was removed, so now the computer was still feeling the pain of that setting, and the solution was to plug in that other keyboard and turn off the Caps Lock. One involved a sort of phantom limb theory, like when a person has a bad itch on his/her right arm but cannot scratch it because the arm has been amputated. There were some other, funkier suggestions. I could do an image restore from some weeks earlier, but I was hoping for something less drastic. But System Restore was not functioning well I had only a few recent restore points, not predating the problem. If not, one solution would be to roll back to an earlier System Restore. It seemed that some rogue program may have screwed things up. Some noted that Control Panel > Ease of Access Center > Make the Keyboard Easier to Use might be set to turn on Sticky Keys.

If that was working for me, I would have to emphasize the 'temporarily' part. Some observed that rebooting would fix the problem, at least temporarily. I had replaced keyboards and found that didn't solve the problem for me - not to mention that I was having the same problem, arising at about the same time, on two different computers. There was the usual assortment of suggested solutions. A search indicated that a fair number of people were having this problem. For some reason, on a system that did not previously have this problem, I would be typing along and suddenly thE DAMN THING WOuld start and then maybe stop typing in all caps, like that. I had a problem, in Windows 7, that apparently afflicted Windows XP users as far back as 2005.

Ctrl key stuck on laptop