OK first of all, Francisco is right, the laptop is super slow and does not have enough RAM, however you should know that there is an issue that is known to affect Intel HD510/HD520/HD540 that is usually fixed by installing a driver update, and it appears that the same driver applies to your HD505 graphics in the N4200, so it’s possible that you will get back to however it was working before if you install the new driver. It’s discussed in this topic:
Read the comments from other people who managed to install it, since the driver installation was not just a click and forget process.
If you have the budget to replace that machine, I highly recommend it. Reply here if you want suggestions for that and let me know which country you live in.