USB mount not working.

[violent23]

Ok, so I figured out if my file explorer is still on the sd card (even if I task kill it) I can not get USB to mount. So I made the home folder the root of the phone. Problem solved right? No, now if I use my music program (3) any time after I can not mount USB. This is not only with 3 it ha s happened with every media player I have tried.
What is going on. How am I supposed to really close these programs so nothing is open in sd? The task kiler I am using is Advanced Task killler. Any insight on this problem would be helpfull.