I have develop reports in Crystall report 9 in VB.Net.Now i have install and upgrade report to Crystall report 10.Now when i run this report through project a database login dialogbox appears with server and database option empty and disabled and only user /password enbale. but when i enter user and password it gives login failure error.Plz help???

You can set a report's datasource connection info via code like in this sample:

    // assign the same database connection for each report
    conn.ServerName = "My_System_DSN";
    conn.DatabaseName = "MY_Database";
    conn.UserID = "SomeUserID";
    conn.Password = "SomePassword";
    for (i=0; i<objReport.Database.Tables.Count; i++) {
        myTable = objReport.Database.Tables[i];
        myLog = myTable.LogOnInfo;
        myLog.ConnectionInfo = conn;
        myTable.ApplyLogOnInfo(myLog);
        myTable.Location = myLog.TableName;
    }