Welcome to emergency mode! Secondary HDD problems [SOLVED]

I bought a specially-built desktop on behalf of an elderly lady friend. It has a 128GB SSD and a 500GB HDD and the PC was demonstrated with Windows 10 loaded.
The first thing I did was to install Ubuntu 16.04 and all was fine – after a while. Then I screwed up, as usual.

Using Gparted I found that Linux was on the the SSD, as expected, although it is sdb and the HDD is sda. I thought it would be a good idea to delete the partitions on the HDD and use it solely as a backup medium. I did this and discovered that there is a lot more to adding a hard drive than meets the eye. A search on the web revealed two useful websites that described the process and I forged ahead. It didn’t work, of course, probably something to do with mounting the drive after the early commands, so I closed down with the intention of tackling it today.

Booting up took ages and resulted in the message “Welcome to emergency mode!” followed by a few unhelpful (to me) suggestions. Hence my call for help.
The easiest solution might be to re-install Ubuntu, which is no problem at all (unless deleting all the partitions on the HDD has screwed things up), but if there is a more interesting way of solving things, I would be very grateful for advice.

Intel i3-2120 CPU 3.3GHz

[EDIT] Using a live USB, I used Gparted to create a partition in the deleted space on the HDD and can save files to it, but still can’t boot normally into Ubuntu.

It would be helpful if you could give us a clue for the current partition layout (from Live USB).

sudo fdisk -l

It is possible that you deleted the partitions off your HDD which could have been used by Ubuntu.
The order of the disks is defined by their connections Disk 1 (sda) = Sata1, Disk 2 (sdb) = Sata2 etc…

Hi Sezo.

After lots of lines like
Disk /dev/ram13: 64 MiB, 67108864 bytes, 131072 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

we have
[i]Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x5fda8cfc

Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 976773119 976771072 465.8G 83 Linux

Disk /dev/sdb: 119.2 GiB, 128035676160 bytes, 250069680 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 0076996B-2802-410E-B8F5-57A88E6376BA

Device Start End Sectors Size Type
/dev/sdb1 2048 1050623 1048576 512M EFI System
/dev/sdb2 1050624 233902079 232851456 111G Linux filesystem
/dev/sdb3 233902080 250068991 16166912 7.7G Linux swap

Disk /dev/sdc: 28.9 GiB, 30998003712 bytes, 60542976 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x6b6d9f39

Device Boot Start End Sectors Size Id Type
/dev/sdc1 8064 60542975 60534912 28.9G c W95 FAT32 (LBA)
ubuntu@ubuntu:~$
[/i]

The SSD does indeed appear to be the last on the cable.
If exchanging the drives and re-instaling Ubuntu is the easiest action then I am happy to do that as there is nothing of importance on the machine.

I think the easiest option is to swap drives and reinstall Ubuntu.

I had a feeling that would be the best course.

…and does it matter that I have created just one big partition on the HDD?

Thank you

Sezo,
I swapped the plugs as you suggested, re-installed Ubuntu and everything is fine.
Very many thanks for your assistance.

Keith