I've eventually got my Ubuntu system running again after a problem with a SATA cable, and all seems well, except, I cannot mount one of my drives which I keep my stuff on.
In folder window, I see three devices in the top left, when I click on each an arrow appears next to it (which I assume means its mounted) and I can view the files.
The last drive, when I click on it, does nothing and then 'Unable to Mount Hard Disk' 'Operation was cancelled' appears. The hard disk then disappears from the list of devices on the left.
It only reappears when I reboot - and I get the same issue when I try to access it?
I used to be able to access this drive before I had the issue with the SATA cable.
Edit: I should add, the machine also has a Win7 install on a separate drive (not the one I can't mount) - If I boot to Windows 7, I can access the drive which I cannot mount in Ubuntu fine.)