here are a couple of options:
1. Kill any SPIDs with open connection then manually set to Single User mode.
2. Take the database Offline, dettach databawse, copy MDF and LDF files (and any other database files) to the second instannce and attach to new instance. Attach back to current instance. MAKE SURE YOU COPY THE FILES, DO NOT MOVE THE FILES.
Thomas LeBlanc, MCITP DBA 2005, 2008 & MCDBA 2000