I dont use MS Office, nor any other office soft much -
this possibly not much help:
I've seen this behaviour a lot in Firefox on Win7 - window fades out & does not respond - I *am* able to alt-tab to other apps. I'm also able to reproduce it once after each FF restart (it seems to be related to a particular plugin) - it recovers after 10 to 20 seconds. It's actually a minor problem for me so I havent bothered following up on it.
Hm, does the entire window go white, or is it more like the app freezes and the window decoration (borders, min/max icons etc) reverts to something that looks win3.x style?
-f0dder
not sure what 3.x looks like - here it's like a transparent white overlay on top of the window - or a faded-out version of window.
edit/ tried to reproduce it for a screenshot and of course it doesnt work now - maybe it requires a reboot - whill check in the moring.