First thing is to get rid of the laptop and find an old, cheap computer, one with a printer port. If you can find an old Point of Sale computer these frequently work well, and are in a very small case, if that matters.
Laptops usually have some battery saving software/hardware built in. You set up a G-code program and tell it to run. Two minutes later the laptop decides you haven't made any keystrokes, so decides to go into the sleep mode.
There is a lot involved in setting up the config files for EMC2. Makes inital setup a bit tricky, but tricky to start is the price you pay for immense capabilities in a variety of environments.
Try using the config setup program and answer the questions as best you can. You might also try using the Sherline setup in EMC2, as it is a pretty plain jane setup. Of course, if this makes it run, you'll have to dig into the config files and start tweaking the calibrations.