My alt key randomly gets "stuck"?

[Shane]

At random times on my Microsoft Ergonomic keyboard it acts as if my alt key is being held down although it is not. This keyboard is about a month old and should not be screwing up like this. Why is this happening? As for the random part it just seems to do it whenever it feels like screwing with me. One time it did it directly after I started up my computer, but usually it happens a couple of hours later.

 

[Bruce]

There could be dirt or food under the keys. My keys would get stuck many times, but I found out that it's because of food under the keys. It still happens sometimes if I eat while on the computer.