What happened to my ALT key????

[MPTech]

I've had my MAME/MAMEWAH running for several months with good success. I've recently been customizing it to add other EMUs (VPinBall, FurturePinball, SNES, SEGA, etc) and I've gotten most of the bugs worked out. 
Last Wednesday I had some friends over for the first time and the competition got intense.  I don't know if this initiated the problems, but they began playing Track&Field (I've never played it before) and really got to banging on the keys.  They moved on to a couple other games and wanted to play a fighting game against each other, so I suggested Marvel.vs.CapCom (one of my favorites).  This is where the problem began occurring. Every time Player1 hit the Kick(?) button (ALT-Key), the Windows Start-menu popped up and MAME lost focus.  After we figured out this is what was causing it, we moved on to some other games.

The next day I started debugging the problem.  I swapped out Control Panels (X-Arcade) thinking the button was damaged(??, didn't make sense, but had to start somewhere).  that wasn't the problem.  I looked at the XArcade.cfg file in MAME, everything looked ok.  I hit the ALT-Key on the keyboard (what the kick button is mapped to) and the Windows/Start menu popped up!!!  I re-booted and shut down all apps, when I hit the ALT-key again (no MAME or anything else running), the Start menu popped up again.  This is very strange and definately not acceptable.

Any suggestions?  I have no explanation for how this could have occurred.  I also tried a different keyboard.
My only thought is to re-format and re-load Windows. I really don't want to go there yet!  And I'm not sure if that would fix the problem.

HELP!!!!!

[Havok]

Check to make sure you don't have any of the accessibility options enabled. Open Control Panel, then Accessibility Options. Especially make sure that sticky keys is unchecked - that may be the problem...