Menu Bar Freezes, stuck with one app, force quit no longer works

I have the unibody mbp 13" 2009 version. It is the base model. Software up to date. I have this hooked up to 24" external LCD with wireless keyboard and mouse.

This happened to me 5 times since yesterday!

I usually use many apps open such as mail, firefox, acrobat, itunes, adium and word. so I switch between these apps quiet often. I noticed this problem when I exposed windows (from word) and selected another app (firefox) to type something, my keyboard no longer worked. I noticed that I was typing on word (previous app that i switched from) instead of firefox. Even though how many time I tried to click firefox, the menubar does NOT switch to firefox. It stays at word. At this time, menubar is still responsive, just does not change the application. So I selected Quit, it does not quit, menubar freezes. I can still do expose but I cannot type anything on other applications. My mouse still works. I open up force quit using keyboard shortcut, the force quit windows pops up, but there is no application on the force quit list. It is blank. At this point, I cannot access menubar at all, even the apple icon. I tried to open up the activity monitor and terminal to quit the finder/alldock manually, these apps do not load up. I just have to restart by pressing on power button for a couple of seconds. It's getting pretty annoying. I've been doing this every 2 hours or so...

Btw, it is just not word to firefox, happened to adium to firefox, firefox to word, vice versa.


Please help!

Thanks!