0. Take Full backup before moving files
1. Set database in single user mode
exec sp_dboption testdb2000,'single user','true'
2. Get path of database files
Exec sp_helpdb testdb2000
3. Save location of all files
C:\Program Files\Microsoft SQL Server\MSSQL$INS2000\data\TestDB2000_Data.MDF
C:\Program Files\Microsoft SQL Server\MSSQL$INS2000\data\TestDB2000_Log.LDF
4. De-attach this database
Exec sp_detach_db @dbname = 'testdb2000','true'
5. Copy all files available in step 2 and paste them to a new location
6. Rename them on their old location, just in case of any issue to revert back changes
7. After copying them to a new location, attach these files from new location to this database, you can attach upto 16 files through this procedure.
Exec sp_attach_db @dbname = 'testdb2000', @filename1 = 'd:\testdb2000\TestDB2000_Data.MDF', @filename2 = 'd:\testdb2000\TestDB2000_Log.LDF'
8. Connect to user database and verify changes, after verification, remove old file from old location