I have a lot of fonts other then the ones that Windows installs.
I always make a copy of my fonts folder to another drive named Fonts Used on This Computer so that if anything happens I can get all my fonts back without a lot of hassles.
Weird that the Post Screen doesn't show, I've never run into that myself.
If fonts alone were the problem you could probably fix it by logging in with a Ubuntu bootable disk and just copying in the Fonts folder, but it sound like this may be related to some kind of hard drive corruption or failure.
Good Luck.
Mike