Ext. USB HD no longer mounts

It is a 2 TB Western Digital Elements USB hard drive. It used to be divided into two partitions which worked perfectly. I than wanted to re-combine the two partitions into one. I went into DiscManagement and deleted each partition. I expected to mount it again as a single 2 TB drive but there is no sign of it. I unplugged the drive and re-plugged it in. I switched off the computer for 20 seconds and re-started.

How can I get my ext. USB drive to mount as one 2 TB drive please? Thanks.

Bastet said:

Have you tried diskpart to clean the drive?
Open cmd prompt/powershell with admin & type
diskpart
list disk
select disk x (where X is the number of the drive
clean
exit
Then open disc management & it should ask you to initialise the drive, allow this & then format it.

Thanks. I managed eventually to re-format as one partition using Disk Management. I have saved your advice for use in the future if needed.