Tab key problems in Vista

[ghell]

My tab key has just started acting strangely in Vista. I first noticed it when I couldn't indent with tab in Visual Studio but now that I have had a play around, I find that I also can't do things like use tab for completion on the command prompt.

Alt+tab still works.

When I press tab, the foreground window always loses focus but nothing else comes to the front (it just seems to deselect the current window and then do nothing).

How can I get it working again?

[ghell]

Hmm, it seems that leaving my computer alone for 15 minutes fixed it.

[ghell]

Apologies for the triple post but it's doing it again and it looks like its going to keep doing it sporadically so I would really appreciate it if anyone could help me to find a solution.