Issues with upgrading and partitions

Hello,

I have a number of issues that may or may not be related.

I'm ruing a dual boot with Windows and 14.04, and recently upgraded from Win7 to Win10 (with a fresh install, after much trial and tribulation).

Now I want to upgrade 14.04 to 15.10 but ruing into problems. Initially I went for a fresh install from a live USB but it just stuck after selecting the download as you ugrade/install repositories options and pressing continue. Then I tried to upgrade from my current OS using system updater, which terminated because of an error (I'll go back and screenshot the details in a minute).

My system partition has been getting quite full lately so I thought that might be having an impact. So my next idea was to open GParted and move things around a bit.

Alas, GParted is now showing my entire disk as unallocated. Al my partitions open fine both in Windows and Ubuntu, so it doesn't seem like there's a problem with the partitions themselves - but maybe my partition tables have been messed up? I'm not sure if this is related to the Windows upgrade though as it's been some time since I looked at GParted.

Anyone have any ideas? Thanks...