SQL 7.0 – Databases show as ‘suspect’

We are bringing a new SQL 7.0 server (running under NT4.0 server, w svc pack 6) into production. This will be a long term data repository for a mainframe system. The database was set up by the supplier of our mainframe software (they have their own front end, etc.) but administering the SQL side of things is our responsibility. Almost every day one or both of the non-system databases show up as ‘suspect. Rebooting clears up the problem, but rebooting the server daily is not an acceptable fix. The mainframe people say this is not a problem they have seen. Any help?