In my 25 years of IT experience programs don't just "become unstable". I've used CC since its inception and never had any problems. I would look at any changes that have happened around the same time (new/upgraded programs), changes to Windows settings etc - change to another program is the most likely cause.
If you want to reinstall, access the Word List manager in CC and select "Files" on the menu bar. You can open the files in Windows Explorer and save them somewhere - there's also a backup option. Take note of where these files are (the Clue DBs are accessible from the level up if you want to save them too). If you want to do this outside of CC then the files (on my XP machine) are here:
C:\Documents and Settings\user
\Application Data\Crossword Compiler 9
It'll be somewhere similar on Win7.
Hope that helps.
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