If Microsoft were to go out of business anytime soon, I would say writing an obituary is the least of our problems.

A company that size doesn't die easily. Look at Apple or IBM or any other large company that had low periods (HP is another example). They have so much money and so many employees, that it would take at least a decade for them to get to a point where they vanished into nothingness (more likely is that they'd get bought up by someone larger).

Anyhow, in the exceedingly small chance that Microsoft were to cease to exist tomorrow, I think the obituary would read something like "Oops!"