Cannot open user default database login failed SQL2005 error 4064 sap 4.7

Hi gurus

i am in the process of creating a copy of another system.

So installed a full system then copied that data files from that system.I dettached the database but now i cant login as the database was the default.

I can log in as master but how do i attached the copied datafiles from another system as iam still facing login problems now

System sap 4.7 enterprise database sql20005

Any ideas welcome