It sounds like the starter is free spinning. I'll turn the key, something will hum, and in a second there will be a grinding noise.. like the solenoid possibly engaging into the crankshaft or whereever it goes? Does this sound familiar to anyone?
-E

 

You can fix that yourself by lubricating the starter. You have to remove it from the car and take it apart. Pretty easy job for the DIY mechanic. Go to Motorvate.ca and look under starter noise fix.