Conflict between NT 4.0 and DOS program

We use a proprietary DOS pension accounting system and a text editor program called V-Edit. Our server and clients are NT 4.0 (SP6). Two PIII 350 and one AMD K-62 550 (with 64 meg of memory) machines continually freeze while in these DOS programs. They are frozen and must be recycled. I did notice that when in these DOS programs, the CPU usage is at 99% to 100%. We have tried multiple remedies with no success. Does anyone have a resolution or suggestion?