To avoid «[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified»:
- Find the ODBC manager in Windows control panel and check the "Drivers" tab. Please note that 64 bit Windows has two different managers for 32 [1] and 64 bit drivers: drivers must match your PHP installation.
- If the required driver doesn't show up there, you need to install it. The free "Microsoft Access Database Engine 2010 Redistributable" package [2] is one of the possibilities for Access and Excel.
- When connecting with odbc_connect(), make sure you are using the exact driver name in the DRIVER parameter: 'Microsoft Access Driver (*.mdb)' will not work if your driver is called 'Microsoft Access Driver (*.mdb, *.accdb)'.
[1] C:\Windows\SysWOW64\odbcad32.exe
[2] http://www.microsoft.com/en-us/download/details.aspx?id=13255