Macbook Air crashing when using 'Show Desktop' shortcut button

This is such an odd problem that I haven't been able to find any troubleshooting for that I don't hold out much hope for a solution. But within the past month or so my 'show desktop' shortcut button which I assigned to left-control originally and then reassigned to to left-option in hopes of fixing the problem, causes my computer to do a quasi reboot. It is not a full reboot, but the screen goes black for a second and then immediately back to the original screen, but Chrome and other apps had been closed (screwing me over on more than one occasion). This has happened a half a dozen times, but not every time I hit the button. Most of the time it brings me to the desktop like it is supposed to, but eventually it ends up crashing my system. I know it is a long shot, but if anyone has seen or heard of this before and has a solution, I'd appreciate it. At this point my only option may be to turn off the shortcut button, but I use the show desktop function a lot that it is worth trying to fix this problem.

I am running OS X Maverick 10.9.4

Wait wait... are you talking about the Mission Control feature, or something else? And how did you assign just the control/option button to activate that? Normally you use one of those in conjunction with another button, not alone. I would definitely recommend against using one of those buttons alone to do anything like that because you'd be activating "show desktop" anytime you tried to use those keys for some other keyboard shortcut. That may even be why you are having this problem.

Yes, it is a one button shortcut. Normally, I would agree that I need to change it to be a two button combination except for the fact that I have had this arrangement on 3 Macbooks over 5 years and never had a problem until now. My work macbook is the one experiencing the issue, but I also have the same model at home with the same software that hasn't ever had this problem. I think it is something directly related to this machine. It may be hardware related. I just wanted to put this out there to see if anyone else has had the same issue.