I have a client who has just been forced to upgrade to a new machine after his antique finally died. The new machine is Win XP Home with SP2 and all updates installed. I've moved all his data to the new machine, but he has one old DOS mailing list program that he just can't live without. But when you try to run it, Windows gives the following error: The NTVDM CPU has encountered an illegal instruction. CS:0f79 ip:001d OP:ff ff ff ff ff Choose 'close' to terminate the application. The machine is new right out of the box and there are no spyware or malware issues. I've tried every possible fix I can find. I've disabled all programs running at startup and also tried running it in safe mode and I still get the error. I've also tried compatability mode to no avail. The program will run just fine on my test machine which has XP Pro SP2. The new box in question is a Compaq although I'm not aware of any pre-installed junk programs that would cause a conflict. Any help would be greatly appreciated.

See if this may help you http://www.techimo.com/forum/archiv... " If at first you don't succeed, Please Post Back "

Might want to investigate the free download program Microsoft Virtual PC 2004. And/or get the user to upgrade the mailing program. Nothing wrong with the new system. Its the old app wanting to make direct hardware calls which are not allowed under the OS. Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.

DOSBox. How To Ask Questions The Smart Way

FYI there is no MS-DOS underbelly in XP, it only has NTVDM an emulation...