Crash Recovery
http://audacityteam.org/wiki/index.php? ... shRecovery
Of course, you need to find out why Audacity crashed. No, that's not normal. People who do this for a long time and then suddenly start having troubles can be suffering from a shrinking hard drive or a drive which hasn't been defragmented forever. Audacity will not work into a drive with no room or one choked by fragmentation -- or both.
Defrag
-- Right Click Start > Explore > Right Click Local Drive C: > Properties (Used, Remaining) > Tools > Error Checking & Defragmentation
In the middle of the largest production and in the face of many effects and UNDO, the free space on your hard drive should never fall below about 15% of the total drive.
It gets big fast. An hour raw show is about 700MB. With production, filters, UNDO and other tools, you could be looking at a 2GB project. Plus room needed for Windows, etc. etc.
Koz