Answer to "How do I replace my keyboard"There is a guide posted here on ifixit for the GE72 6QF (note it’s the 72 6QF) that would likely be very helpful; the exact steps may be the same -or close ; I have no personal experience with either model so can’t say for certain. It might be worth it for you to attempt the disassembly using the guide; If you note major differences you could try to infer the next steps, or back out and look for a more exact guide if you don’t feel comfortable proceeding. If you do see differences and work through them successfully you could post your own guide. MSI GE72 6QF Apache Pro Keyboard Replacement by https://www.ifixit.com/User/2171874/Rile... with contributions from https://www.ifixit.com/User/1338065/Mart...
Answer to "Where cpu designation on C720-2103"Intel Celeron 2955U / 1.4 GHz I found this by searching for (no quotes) ‘specs C720-2103’ on a very popular search engine; The top result pointed me to a CNET review; the model number matched as did your description of ports.