Ok....I got a way....making a DSN connection does it all....here are the steps:
My Computer ---> Control Panel ---> Administrative tools ---> Right click on ODBC data source(64 bit) ---> add ---> choose oracle driver ---> finish--> then window will open asking some username password and DSN name ---> create DSN use previously mentioned code like this:
Dim conn As New ADODB.Connection
conn.Open "DSN=dsnName;uid=xyz;pwd=x123"
Thats it!! :) :)
If you want to make a DSN less connection then use this:
Dim conn As New ADODB.Connection
conn.Open "driver={driver name in your machine};uid=xyz;pwd=x123"