Just tell us what has broken...
If there are problems with the FILES (the stuff stored in the FOLDERS in your ZC installation) then you can restore these FILES fairly easily - as long as they are the same VERSION as the original files.
Sometimes, these FILES get corrupted, making your store inoperative.
This does not mean the database has been damaged.
Before you overwrite anything, you must determine if the problem is a corrupted file (or files), or if the database is faulty.
Separate tests are required to establish whether it is a FILE problem or a DBASE problem.
When you have established where the problem lies, you then tackle it.
My advice is to be VERY CAREFUL about messing with the database, as fixing this is extremely difficult... especially if there's nothing wrong with it in the first place.
Again, describe your problem and we may be able to advise the best solution.