Qsqldatabase can't connect to ms access database file

[Hadi]

hi
i have a ms access file ...my file name is mydb.mdb and i use win7 64x and Qt 5.1 msvc 2012.
now i want to load my db file and access to it's saved information.i put my db file in my hard disk C drive.
my code is:

@#pro file
QT +=sql
@

MainWindow.cpp
@
QSqlDatabase mydb = QSqlDatabase::addDatabase("QODBC","mybasedb");
qDebug()<<mydb.isValid()<<endl;//true
mydb.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb, *.accdb)};FIL={MS Access};DBQ=C:\mydb.mdb");
mydb.setConnectOptions("SQL_ATTR_ODBC_VERSION=SQL_OV_ODBC3");//force ODBC3.x behavior
mydb.setHostName("localhost");
mydb.setDatabaseName("mydb");
mydb.setUserName("");
mydb.setPassword("");
bool opened=mydb.open();
if(opened)
QMessageBox::information(this,"Yeah","It's Perfect!");
else
{
QMessageBox::information(this,"Oh",mydb.lastError().text());
qDebug()<<mydb.lastError().text()<<endl;
}
@
now i am trying to connect and open my db file but it can't open db file.
how can i solve it???

the error message is:

bq. [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified QODBC3: Unable to connect;

also can i load db file as bytearray or file object and then use it by QSqlDatabase?