We can't help unless we know what sort of problem you are having. Can you give us some details, please?
I've reset my preferences.
It seems to have fixed it.
What preferences will I have lost?
My short cuts still seem to be there, along with my personal work spaces.
You've lost all of the customizations you would have made in preference settings, along with document and printer presets, and the Open Recent files list. You might want to take a look at Replace Your Preferences for more details about what's lost, and how you can back that stuff up for the future.
This has started again.
The 200 page document has to go to press today.
Shall I simply tell my family I can't pay the mortgage?