Problem with W Key

[tmbutcher]

I'm having an unusual problem, and I was wondering if any of you might be able to help me sort it out. It's a bit difficult to describe what happens (and even more difficult to google the problem), but basically, the issue is that the W key on both my iMac (with the old wired aluminum keyboard) and on my 2010 MBP is behaving very oddly.

Essentially, the Mac doesn't seem to recognize it the first time that I type a W—it just acts as if I had pressed no key at all. After that, the W key seems to work absolutely perfectly, until I leave the W key alone for a few minutes, at which point the problem begins again.

The weird thing is that this is happening on both my iMac and my MBP, so I'm thinking that there must be something in OSX that is preventing that initial recognition. Obviously this isn't a huge problem, since I only have to press the W key again to get things to work well, but it is rather annoying, and tends to lead to a fair number of embarrassing typos.

Anyone have any idea what might be causing this strange problem? Or else an idea of how I could track down the culprit?

[fracai]

First step, create a new user and see if the behavior occurs there. You could also try booting from installation media, a full backup, or a live CD to see if it still occurs. If it does, it's more likely to be hardware. If the behavior disappears under a new user account, it's something with your account and you could try clearing caches or looking for corrupt preferences.

Did it start happening on both machines at the same time?
Do you have a 3rd party utility that you're using on both systems that modifies key commands or actions?

Do you have AppleCare on either of these?