Autosave every 15 minutes

[mania112]

I have this code, and it's not working:

Sub MyMacro()

End Sub
dTime = Time + TimeValue("00:15:00")
Application.OnTime dTime, "MyMacro"

ThisWorkbook.Save
End Sub

Can someone help me setup an autosave vb in Excel 2007 - I want a SAVE not a SAVE AS.

thanks