The "No SIM Found" error in Mastercam X5 is a common licensing issue, usually referring to a missing or unrecognized HASP (Hardware Against Software Piracy)
If you have a USB Dongle plugged into your PC, set the "Mode" to HASP and "Type" to Local.
Windows should never sleep your security dongle.
If you are unable to resolve hardware issues, you might explore the Mastercam Demo/Home Learning Edition