OMG! I had not idea you were in such a far flung time zone. Yes, of course, we can defer to whenever is convenient for you. I am so very grateful for your assistance with this. Thank seems rather lame. I won't shut down my computer.

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sda - 500 GB / 465 GiB - CHS 60801 255 63

The harddisk (500 GB / 465 GiB) seems too small! (< 521 GB / 485 GiB)
Check the harddisk size: HD jumpers settings, BIOS detection...

The following partition can't be recovered:
Partition Start End Size in sectors
> MS Data 976773119 1018736638 41963520










[ Continue ]
NTFS, blocksize=4096, 21 GB / 20 GiB

No problem. I didn't expect that extra screen (this is new territory for me too, now).

Press Enter (Continue is the default action)

Edit: Once we can get it actually searching, then I can call it a day for now.

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sda - 500 GB / 465 GiB - CHS 60801 255 63
Partition Start End Size in sectors
>P MS Data 2048 1050623 1048576 [NO NAME]
D MS Data 1050624 968617983 967567360
D MS Data 934809600 976773119 41963520
D Linux Swap 968617984 976771055 8153072








Structure: Ok. Use Up/Down Arrow keys to select partition.
Use Left/Right Arrow keys to CHANGE partition characteristics:
P=Primary D=Deleted
Keys A: add partition, L: load backup, T: change type, P: list files,
Enter: to continue
FAT32, blocksize=4096, 536 MB / 512 MiB

Well it appears to have found the Windows partition that you replaced with the Linux partition. I don't think that helps us though.

Just to check though:

Can you highlight the line "D MS Data 1050624 968617983 967567360".

Then press P to list the files on that partition.

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
MS Data 1050624 968617983 967567360
Directory /

>drwxr-xr-x 0 0 4096 14-Mar-2018 08:17 .
drwxr-xr-x 0 0 4096 14-Mar-2018 08:17 ..
drwx------ 0 0 16384 4-Oct-2016 20:01 lost+found
drwxr-xr-x 0 0 4096 31-Mar-2018 08:31 boot
drwxr-xr-x 0 0 12288 31-Mar-2018 17:21 etc
drwxr-xr-x 0 0 4096 31-Mar-2018 07:57 media
drwxr-xr-x 0 0 12288 31-Mar-2018 08:27 bin
drwxr-xr-x 0 0 4096 28-Jun-2016 05:37 dev
drwxr-xr-x 0 0 4096 19-Oct-2017 19:23 home
drwxr-xr-x 0 0 4096 17-Jan-2018 04:57 lib
drwxr-xr-x 0 0 4096 17-Jan-2018 04:57 lib64
drwxr-xr-x 0 0 4096 28-Jun-2016 04:59 mnt
drwxr-xr-x 0 0 4096 17-Mar-2018 08:14 opt
drwxr-xr-x 0 0 4096 12-Apr-2016 13:14 proc
Next
Use Right to change directory, h to hide deleted files
q to quit, : to select the current file, a to select all files
C to copy the selected files, c to copy the current file

Highlight home and press Enter.

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
MS Data 1050624 968617983 967567360
Directory /home

>drwxr-xr-x 0 0 4096 19-Oct-2017 19:23 .
drwxr-xr-x 0 0 4096 14-Mar-2018 08:17 ..
drwxr-xr-x 1000 1000 4096 30-Mar-2018 22:51 ken
drwxr-xr-x 1001 1001 4096 27-Jan-2017 21:42 kad
drwxr-xr-x 1001 1001 4096 31-Mar-2018 17:26 drew









Next
Use Left arrow to go back, Right to change directory, h to hide deleted files
q to quit, : to select the current file, a to select all files
C to copy the selected files, c to copy the current file

That is unusual. Did you change your login name from ken to drew yesterday?

Before this mess up, I had tried to change my user name and the system was showing me as Drew(ken)@X200CA. Then after this mess happened and I was having trouble getting in, it presented me with ken and drew dangerfield (my surname). When I selected my full name, it showed "drew" and now its showing two users - ken and drew.

I have to be away from the computer for about 10 minutes. If you want to log off for tonight that's fine with me.

I'll head to my kip at 5.

When you get back, can you please paste the output from:

drew@ken-X200CA ~ $ ls -la /home
total 20
drwxr-xr-x 5 root root 4096 Oct 19 19:23 .
drwxr-xr-x 23 root root 4096 Mar 14 08:17 ..
drwxr-xr-x 22 drew drew 4096 Mar 31 17:26 drew
drwxr-xr-x 18 drew drew 4096 Jan 27 2017 kad
drwxr-xr-x 81 ken ken 4096 Mar 30 22:51 ken
drew@ken-X200CA ~ $

Right, I think we're getting at the nub of the problem. When did you try changing your username. Was it very recently?

In the meantime, select ken and press Enter.

No, it was at least a few months ago.

TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
MS Data 1050624 968617983 967567360
Directory /home/ken

>drwxr-xr-x 1000 1000 4096 30-Mar-2018 22:51 .
drwxr-xr-x 0 0 4096 19-Oct-2017 19:23 ..
-rw-r--r-- 1000 1000 675 4-Oct-2016 20:05 .profile
drwxr-xr-x 1000 1000 4096 29-Nov-2017 17:09 .mozilla
-rw-r--r-- 1000 1000 220 4-Oct-2016 20:05 .bash_logout
-rw-r--r-- 1000 1000 4000 4-Oct-2016 20:05 .bashrc
drwxr-xr-x 1000 1000 4096 29-Mar-2018 18:44 .config
drwx------ 1000 1000 4096 30-Mar-2018 20:01 .cache
-rw------- 1000 1000 121 30-Mar-2018 07:14 .Xauthority
-rw-r--r-- 1000 1000 6201 30-Mar-2018 23:48 .xsession-errors
-rw------- 1000 1000 29 30-Mar-2018 07:14 .dmrc
drwxr-xr-x 1000 1000 4096 18-Mar-2018 08:36 Desktop
drwxr-xr-x 1000 1000 4096 30-Mar-2018 19:57 Downloads
drwxr-xr-x 1000 1000 4096 4-Oct-2016 20:18 Templates
Next
Use Left arrow to go back, Right to change directory, h to hide deleted files
q to quit, : to select the current file, a to select all files
C to copy the selected files, c to copy the current file

Ok, nothing of obvious interest there.

Select and enter ..

Select and enter drew

I swear that I did nothing strange, unusual or out of the ordinary to precipitate this problem. After the debacle with the Virtualbox update was resolved, my computer was running fine for a few days. I turned it off Friday night (Mar 30) and when I booted it up on Mar 31, it started what appears to be a fresh install of Mint 18.3 I did install some updates from Mint's Update Manager and I'm convinced that' where the problem lies.

BTW I am still experiencing horrible latency in keystrokes. Very slow and jerky. Something is very definitely amiss. If we can just manage to get my data transferred onto a USB stick, I'm outta here. My confidence in Mint has plummeted.

Thanks again for your help.