Windows 2000 DOS program slows PC

I have a MS Windows 2000 Professional computer and when i access a DOS based program the CPU spikes to 100% usage and it appears that 95-99% of the usage is by the DOS program (NTVDM.exe). It slows down to almost a stop of all other programs on the computer while it is in use. I have searched everywhere i can think on the internet but the only fix i can find is simply not using the DOS program. Is there a way to fix this annoyance without eliminating the DOS program? I have all Windows updates to date installed. It has 256 MB RAM and AMD Athlon XP 2000+ processor.