Keyboard Occasionally Remaps Itself

I'm using a Toshiba Satellite A15 laptop running Windows XP SP2, and my keyboard tends to remap itself. At first I thought it was limited to Microsoft Word, but I've also found it happens in other programs as well; only the programs where I do a lot of typing. What happens is that I'll be typing for a while, and then the keys will start getting mixed up. If I save my work, and restart the program, the keyboard returns to normal (the problem only happens in the program window; explorer tends to work fine). Also, after I restart the program, the problem tends to happen faster each time I try it, until it's useless to continue work without restarting the whole computer. I've tried various spyware scans and have used virus scan as well (McAfee, AdAware, Spybot, etc.). I also tried cleaning out the keyboard for dust, but I'm not sure what that was supposed to do. I would really appreciate any help.

 

Today I checked the Toshiba website, and I found a BIOS update, but I'm curious whether this will help my problem or not before I go through with it. The support site doesn't mention exactly what the update does for me, so I just wanted to ask the forum in case this is an unnecessary step. Otherwise, all the other updates on the support site for Toshiba don't apply to me.

 

I've come across a new discovery. I was not formerly familiar with the American-Dvorak keyboard layout, but I think it has something to do with my recurring problem. I've noticed that on a diagram of the keyboard, my switched keys match up to those that appear on the diagram. However, I still don't know how to stop my computer from switching into this mode. I'm quite comfortable with my qwerty right now, so any help would be great.