I am unable to download pictures from my Cannon Power Shot SX10IS.

[mk]

Hello, 

I am unable to download pictures.  I've replaced the batteries, replaced the memory card, and tried several different USB cords.  I have an Apple Mac Book.  I've tried downloading to my apple and my husband's PC, and was unsuccessful.  Does anyone have a suggestion as to what to do?

Thank you

[jfo]

Have you ever been able to download pictures? If so, what steps did you take that aren't working now?  If not, what are you doing that isn't working?