Thanks BigBambi for your response. I have been copying files into the microsdhc using an external usb adapter. The c250 plays my FLAC files contained in the microsdhc card with no problems.
The problem is when I try to recharge the batteries and insert the c250 cable into the computer. Normally, without the microsdhc card, the c250 will eventually boot into the OF. No problem. When the microsdhc card is in the player, the c250 will not boot into the OF, but freezes up.
So what I have been doing is one of two things:
A. After it freezes, I need to press the on/off button twice and it takes me right into the OF.
or
B. I keep the "<<" button pressed, and then connect the usb cable to the pc.
I really wished that I could just plug the usb cable into the pc without having to follow either A or B.
Note: I've discovered that my c250 does not really freeze, but takes a very long time for it to get into the OF when I connect the cable to the pc with the microsdhc card inside.