This is only a suggestion, and can and is able to sometimes cause big problems. So please weigh your choices carefully. (and a fresh backup of your stuff)
The 38.8 kernel has been a known problem for many, including me personally. Upgrades are available. There is a 38.10 or higher available for a proper and easy install through Mint Update.
Log in to Mint Update, go to Edit -> Preferences -> Levels tab, and check the Visible box only for levels 4 and 5. Close the Preferences window, and be sure to hit the Refresh button. You should now see new updates available, go through them, the latest available kernel should also be in the list. I suggest that you use the Select All button (same as a dist-upgrade), and then the Install button. Close when completed.
Since the kernel has changed, and possibly some important xorg updates, I suggest a cold reboot. (complete shut down, wait a few minutes, then start up again)
Warning : When being installed, the new kernel is compiled with your required modules and drivers. Some times you will need to use the Hardware Drivers app to re-install the proprietary nvidia drivers. (I am confident you will not need to do this). But you have been warned.
Good luck whatever you decide, and keep us informed of your progress, or if you have a question.