Ctrl key also presses letter "a"

Hi folks,

When I press the ctrl key on my laptop it sometimes behaves as if I've pressed the letter "a" as well, so it selects everything on the screen, or it types the letter "a". It happens with both the left and the right ctrl keys so I think it's something to do with software rather than a physical problem. It happens even in safe mode. It's more likely to happen when I press and hold the ctrl key than when I just tap it. I've tried uninstalling the keyboard driver and restarting they computer but that made no difference.

My system is
Toshiba Satellite L500D laptop
Windows 7 Home Premium 64 bit, with service pack 1

Any suggestions for how to fix it? Thanks in advance

Loxy

P.S. I don't know whether it's related but a few months ago I had BSOD problems caused by a USB driver
BSOD on Toshiba laptop when sleep or idle for a while

I doubt that I'll be of much help on your problem, but can you test with an external keyboard? Maybe you can borrow one from a friend. Also, how does the W7 native on-screen keyboard act? Does its Ctrl key work as expected?

Testing in the safe mode was a good idea. You might also work thru this:
Troubleshoot Application Conflicts by Performing a Clean Startup

I had to stop suggesting Toshiba laptops because the last 6 that friends/family purchased all had weird keyboard issues.

Thanks for the suggestions guys.

Windows onscreen keyboard doesn't suffer from the same problem. Nor does an external keyboard. So, for the short term, I can fix the problem by using an external keyboard.

@fireberd: At first I thought it was a hardware problem too. But then that wouldn't explain why both ctrl keys have the same problem (or would it?)

The left and right Crtl keys are indeed different, but they both send signals to a common (defective?) set of chips.

Replacing a Toshiba laptop keyboard is not too hard... just take your time and make use of the videos that fireberd linked to.

While you have it apart, you might want to clean the fan and vents... but don't let compressed air spin the fan too fast.