I just leave my car for one or two week without driving because I was out of town, but now I cannot start it again, I checked the
battery and the spark plugs, they are still in good shape. When I try to start the car, there is "tach, tach.." sound. Could anyone help me with this problem. Thanks a lot!!!

 

Battery is a little too drained to start or cables are dirty or solenoid is bad. I'd vote the battery drained from your memory wire to the radio (which usually never turns off).