First of all, the search service is not working and doesn't return any
result.

I stopped the service and restarted, then it says "WSS_Search_XXXXXX on
YYYYYYYY(DB server) contains user-defined schema. Databases must be
empty before they can be used. Delete all of the tables, stored
procedures and other objects or use a different database. "

I found that stopping search service won't uninstall the search service
nor delete all index files. Any body knows how to fix these two
problems?

1. WSS Search not working
2. Stopping Search service won't delete index files.

Any help will be deeply appreciated.