autocad 12 Crash/fail to boot

[JAE1095]

this instance of '12 has been running perfectly for months, and this afternoon when I attempted to move from 2d to 3d it threw an unhandled exception & fatal error. I restarted the machine but acad won't restart. It just kind of hangs there. What causes this, and do I have to reinstall?

Also, I sent an error message to autodesk, who sent me an automated email about a maintenance update being available, which also fails to load when you click the link (internal server error). Are these related? It's very strange for all of this to happen at once.

[pendean]

AutoCAD 2012 updates are here, download the entire file them install instead of trying to install through the web connection:
http://knowledge.autodesk.com/support/autocad/downloads#?cg=Downloads&p=AutoCAD&v=2012&doctype=Servi...

[JAE1095 · Accepted solution]

Fixed! Easier than I thought. I still don't know why it broke down today, but the service pack made it work again. Thanks very much!