You don't have cryptsetup installed on your second computer, install it via: sudo apt-get install cryptsetup
Once you've installed it, double click on the encrypted volume again and it should mount for you.
[Edit]
The error from your mount command mount: unknown filesystem type 'LVM2_member' tells us that it's an LVM group, and needs to be mounted slightly differently.
Hopefully the following will provide the information you need to get it mounted, based upon my system.
$ sudo pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 ubuntu lvm2 a-- 99.51g 0
This tells us that the volume, ubuntu is on the physical volume /dev/sda2. We then need to use the lvdisplay command to list the logical volumes in the group.
$ sudo lvdisplay /dev/ubuntu
--- Logical volume ---
LV Path /dev/ubuntu/swap
LV Name swap
VG Name ubuntu
<snip>
--- Logical volume ---
LV Path /dev/ubuntu/home
LV Name home
VG Name ubuntu
<snip>
--- Logical volume ---
LV Path /dev/ubuntu/root
LV Name root
VG Name ubuntu
<snip>
From the above we can see that I've got a home, root and swap. To mount the home partition from this group I would run the following command:
$ mount /dev/ubuntu/home /mnt/disk
If you're unsure how to modify this to suit your needs, edit your question again with the output of the pvs and lvdisplay commands. You might want to take a look at Formatting Help as well.
I am assuming that you used the "Encrypt the new Ubuntu installation" or its manual equivalent; that is, your hard disk is encrypted by LUKS and in the encrypted container you have an LVM volume group.
Before starting, make sure that you have cryptsetup and lvm2 installed; if not, install them:
sudo apt-get install cryptsetup-bin lvm2
Take the drive out and put it into a USB enclosure.
Connect it to a working computer running Ubuntu or any other Debian derivative; you can even use a live DVD or USB flash drive for this. Say that the disk is seen by the system as /dev/sdb.
Find out which partition on the disk is the LUKS container:
for p in /dev/sdb*; do
sudo cryptsetup isLuks $p && echo $p is a LUKS container
done
For example, suppose that you found out that /dev/sdb2 is a LUKS container. Open it:
sudo crypsetup luksOpen /dev/sdb2 old-hard-disk
LVM should automatically detect the logical volumes; see if it did so with
sudo lvs -o full_name,size,seg_pe_ranges
If not, you may have to trigger LVM recognition with sudo vgchange -aay.
Now you have the logical volumes in /dev/mapper. Mount them onto some directories.
Best Answer
Assuming you have a computer that runs Ubuntu or an Ubuntu community flavour,
If you wipe the first mibibyte, overwrite it with zeros, the data on the [rest of] the drive does not make any difference, and you can use any tool for this purpose.
You can wipe the first mibibyte in a safe way with mkusb.
After that you can [install and] use gparted or some command line tools to create the partition table with partitions and file systems that you want. It might even work without wiping the first mibibyte (depending of on the data in that part of the drive).
Links: