While this newsgroup is about SQL Server 7.0 and 2000 Full-Text search...
SQL Server 6.x did not have mdf files, they were "dat" files and internally
very much different from SQL 7.0 or 2000 mdf files. I'd strong recommend
that you upgrade to SQL 2000, and for now search
for SQL 6.5 database KB article on how to
expand the database, as well as review SQL Server 6.5 Books Online, they too
explain how to expand a SQL 6.5 database...