My laptop ( a Dell Inspiron 6000) stopped booting up today.
While I was immediately worried, I knew that I lost nothing of value. I have been using Microsoft Live Mesh to sync My Documents, so all of my important documents were immediately available in the cloud.
A couple minutes later I had downloaded Ubuntu and put it on a flash drive. I used that to boot up my laptop, and saw that all my files were intact.
I am delighted at how much more user-friendly Linux is now than the last time I used it.
While I still need to investigate the best way to recover my work flow from this situation, none of my files were lost, and I was rapidly back to almost full productivity (no automatic Mesh syncing to Linux, sadly).