You would be amazed at the capacity of a CNC machine to create a mess. If it is MDF based cutting then the fine dust gets EVERYWHERE. Metal is worse, as it is conductive and I have lost one motherboard this year from swarf ingress. Even with dust extraction some local filtration is a must. I would recommend one on your face to start with, then the PC should be in a case with filtered air being blown in. If you are running Mach3 and a parallel port, then a laptop is trouble because of timing issues and power saving.

I don't know about AutoCAD nowadays, but I run version R14, which is at least 20 years old, but does what I want. On a modern PC that can't be hogging too much in the way of resources.