Harrison,

I  have the same problem.
It happens because you use different or different version of OS with
differents or more device driver.
I solve it  making more then one CONFIG.SYS copies and one for ORCAD with
only the device I need.
I have made a .BAT that copy the CONFIG.OCD into CONFIG.SYS and reset the
machine when I need it.
It WORKS with MS DOS 5.02 . On newer OS you can change CONFIG.SYS on the
fly.

                       Claudio Rachiele IW0DZG