Applications randomly alt-tab? (especially full screen games)

I'm not sure when this began, how it happens, or why it happens, but it is quite bothersome and apparently random.

Just randomly throughout the day my computer will just go to the desktop. I could be in a full screen game and it will just immediately alt tab and present the desktop. Or I could be watching a movie and this happens.

Sometimes it happens once every three hours and other times (just today actually) it did it twice in the span of 30 seconds.

I am positive I am not pressing a hotkey because I launched a game, sat idle, and noticed it alt tab while cleaning up around my room after about 20 minutes.

Sometimes it goes days without this happening.

Specs: Windows 7 Ultimate 64 Bit, 10 gigs of RAM, GeForce GTX 260, Intel Xeon CPU.

I also have basically nothing running when it happens other than the game and FireFox.

My FireFox add-ons: Adblock Plus, Download Statusbar, Firebug, FirePHP, lazarus form recovery, tree-style-tabs, yslow.

I doubt FireFox is causing the issue but I figured I'd include it anyway because it is the only application I have running when it happens.

As for user processes I have running: VCDDaemon (context menu for virtual clone drive), razerhid (mouse), OSD, taskhost, dmw (desktop window manager), anyfullscreengame, audiorepeater, netsession_win, explorer, razerofa, tsvncache, firefox, plugin-container, and EKIJ5000MUI (printer).

Whew. Okay. That was a lot of information. If someone could diagnose this I would be most grateful for this has been around with me for years.. Thanks for reading!

PS: I doubt it's a virus because I never download illegal software and pretty much only browse Reddit and Stackexchange and play games. If it was a virus it would be a pretty lame one.. Hah..

If you have excluded software issues, try another keyboard. Mine sometimes open start menu after pressing ECS - reason? - blocked CTRL key. Try pressing few times alt key, it might help