Forward me to the right direction please.

Here's the situation, I was getting this error earlier C:\WINDOWS\SYSTEM32\AUTOEXEC.NT. The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close" to terminate the application. I had a friend help me out and it just got worse, now were getting this error when we try to access cmd command.

C:\WINDOWS\system32\cmd.com
The NTVDM CPU has encountered an illegal instruction
CS:0ddc IP:001f OP:ff ff ff ff ff Choose 'Close' to terminate the application

I'm sure I'm not the only one that has gone through this. I would be very thankful and bless if someone can point me in the right direction.

Thank you,
K