LiveUSB and Live install stop working

Hi,

I created a LiveUSB with Federa 15 (I need software on the older release)
and have had the the USB stop working on me after a couple of uses. I suspect
the problem lies in the fact that shutdown/reboot seem to hang and that the OS
becomes corrupted. Is there a way to get the boot loader (GRUB?) to show me
the boot process so I can see where/why it is hanging?

I'm also having problems booting from a removable USB hard drive even though
'Install to hard drive' has reported success many times.

Does anyone have any tips for installing to a removable USB hard drive?

Thanks,
Darren