Set up using AMC AB15A100 drives, brushed DC motor Prototrak Plus with Encoders

Todd, many thanks! The keyboard has 2 flashing light, 1 is the cap lock light, don't recall the other light name that is just beside it. The keyboard and mouse do not work. I am going to try a different keyboard, current 1 is round plug, going to a USB style. I have reviewed the link you have sent & reread your message, as you suggest this may not be easy to find.
When I re-zero this time, I will set the hand wheel to 0.0, so no need to dial in again.

Many thanks!

Blinking keyboard leds indicate a kernel panic . A likely cause is failing RAM. Run memtest86 on the computer for a few hours and see if it finds any errors.

arvidb, thanks for the help! I have read your link & I will be looking for a RAM issue. In the past, I have had some success with cleaning with electronic contact cleaner & reseat memory in other computers.

Many thanks!

Edit: I cleaned & reseated memory, but program stopped (I have not gotten through this program, 1 time completely, yet) again, different place every time, the computer has 2 slots, I found 2 (1 GB each) used RAM on eBay, will be here end of the week. This replaces 1 each of 512.
Many Thanks!

arvidb, many thanks. I ordered 2 pc. of 1 GB used RAM from ebay, only 1 tested good, so now only 2 slots in computer, so 1 GB in slot 1 & 512 in slot 2. Ran last program that had issue, all worked well and as expected!!

Many thanks!!

Many, many thanks to all the members for a real informative forum.

Many thanks!

Hope all are well and staying warm!! I have been using my mill as usual (after installing the RAM (it had 512; I added 1 GB; now has 1 GB plus the 512, as memory)) this message would appear, my thinking was slot 1 does not match slot 2 in memory:

"Keys: Press F to fix the errors, I to ignore, S to skip mounting, or M for manual recovery"

I would press F to fix, but it would appear next time it was booted up.

Today after running a few different parts & was starting to open a new part from the USB, and it got hung up opening new part; a new message appeared on-screen:

Could not start the X server (your graphical environment) due to some internal error. Please contact your system administrator or check your syslog to diagnose. In the meantime, this display will be disabled. Please restart MDM when the problem is corrected.

Now has this on screen:
Linux Mint 17.3 Rosa cnc tty1
cnc login:

I have tried the login p/w & name, w/o any luck getting past this screen.

Please, all help would be warmly welcomed. Many thanks!

Edit:
After pondering, I pressed the power on button, for 5 seconds, computer went off, waited 15 seconds powered back up and all is good. There is still a message (not exact same) on start up, I did what was suggested, will try in the morning.  Many thanks!!