cmd reboot NTVDM "the cpu has encountered an error"

*I got this email 10 days ago. Unfortunately, I've never come across this error before, and a google search came back with no results:
Good Day!

I already fixed my broken computer using your files that I have downloaded from your site.
I just want to personally thank you for that. But, I have another problem, I cannot open the cmd, whenever I want to open it, it restarts. And some other applications are the same, the message was about the NTVDM, "the cpu has encounter an error". Please help me regarding this matter.

Thank you. & more powers,

*I emailed this response the next day:
I have to say that sounds rather odd. Do you have a "special"
configuration of maybe the system files or program files in a location
other than the default? Multiple hard drives perhaps?

If you haven't already, I'd suggest a backup.
*No responce yet