vb6 exe in windows 7 getting error Microsoft ODBC Driver Manager Data Source name not found and no default driver specified

We have one v6.exe application in windows 2003 server .short cut of this vb6 exe working fine in all windows xp client pc with help of  system dsn name as ABC( for sqlconnection string). Now we changed all windows xp client pc to windows 7 and accessing the application from  windows 2003 server . All most all are working (95%) fine. Some screen are not loading and getting error as Microsoft ODBC Driver Manager Data Source name not found and no default driver specified. I am 100% sure that my  connection string are correct.  Only thing is we are using both system DSN and user DSN in windows 7 client pc.
Before win xp client PC we used only user DSN.  if use both dsn in windows 7 only our application running the 95%. So my doubts is , why some screen are not working . Why its is  showing Microsoft ODBC Driver Manager Data Source name not found and no default driver specified error in some screen. Plz let me give some tips. I can't make windows 7 compatibility mode. Its showing as disable mode.
May be if it There are 2 versions of ODBC to worry about on 64-bit machines: .
Or any extra dll we need to add it ?


I saw one thing behind it. Where ever the ADODC contol placed  in the form , I am getting issue there also. So ADODC  is not working in windows 7