Can I upgrade a robot?

Can I upgrade the electronics and software for my robot? My robot is a
20 year old, 4 axis, stepper motor, 10kg pick and place.

I need the robot to cut out shapes drawn in Autocad 2d or similar.

The drivers for the steppers are probably in good condition but the
unit is not running to test it. The other electronics are plc not pc
compatable. It is all 20 year old original high quality
scientific/industrial.

I'm out of my depth with electronics, is new componentry compatable
with old stepper drivers??? Can the circular interpolation of a
robot be directed through software to cut from autocad???

Any help would be greatly appreciated...

Regards Pete