Keyboard Bug- stuck on alternate kyes, or repeating a key.

Hello.

After a little use, my keyboard types with the alternate keys (press alt and type ie. ©ƒ˙∆¨†®ƒåœ∑) - have tried 3 different keyboards, one wireless, and in different ports, it is not a keyboard issue.

When I restart, everything is fine, but after a certain period of time - and this fluctuates, it starts typing with the alternate keys only. I have reinstalled the OS - entirely, and this still happens. For some reason i thought it was the java update - since this only started about 2 weeks ago, when I updated the computer via the software update (which had the Os update plus java update).

I also use Adobe products heavily on this computer, but I don't see why they would suddenly have of started being buggy...

I actually have an idea - when this was happening to me last week, sometimes instead of that , what would happen is - i would type a letter, any letter, say "G" - and the computer would infinitely repeat it, until i restarted. So maybe the same thing is happening with the alt key, it just happens to crash on the alt key more often than another key?

So maybe the problem is that the keyboard gets stuck on a letter, the letter dependent on what I'm typing when it crashes...

So one key keeps getting stuck, and it most often is the alt key.

Please help! This is so frustrating, and I called mac who simply told me to reinstall the OS. Which I did, Which hasn't helped.