I upgraded WIN 2K to WIN XP 32 bit SP3 without any problem and it worked fine for months. Now I get a message: 16 bit MS-DOS Subsystem C:WINDOWS\system32\rundl.32.exe The NTVDM CPU has encountered an illegal instruction CS:0018 IP:003b CP:f0 choose "close" to terminate the application My knowledge of computer is very basic. I was trying to uninstall Kaspersky 3.0 to install AVG antivirus and no matter what I click in the Control panel I get this error message and I cannot open anything in the Control panel ...even Add/Remove programs. Otherwise I can surf the internet, send/receive emails OK. I get this error message three times even when my computer is booting. Each time I choose the "close" option to let it finish booting. How can I get rid of this error message? Thank you.
https://www.google.com/#q=ntvdm+cpu+has+encountered+an+illegal+instruction+xp you should check out several threads in the above search page, several possible solutions discussed, most come down to an infection. NOTE: when you uninstall some antivirus' they provide a removal tool to accomplish this as regular removal does not work.