ADO Connection pointer problem

Hi All,
I have a Query reg. the ADO Connection pointer.When,I create a DB using ADOX and establish connection to the same.Under this scenario I ca get the Connection pointer successfully.But, if already that DB is present I need to get the connection pointer for that DB.The problem is I could not get the Connection pointer to that already existing DB.I have checked the Connection String for establishing connection with this DB.Still it failed saying E_FAIL.Where is the problem ?

NOTE :The already existing DB path is obtained fron Registry.

Thanx in advance for the help!

Regards,
yamini