There are any number of ways to fix the problem, the problem is not all of them work in all situations. Here are two quick things to try that are non invasive and dont require a lot of know how to do.
1. Reinstall your video drivers. Its a known issue with Win8 and Win10 to have an update foul up the drivers in a way that the taskbar and start menu stop working.
2. Force the OS to do a safeboot, then revert back to a normal boot. To do this, hit the windows key + r to bring up the run dialog box. Type in MSCONFIG. Select the Boot tab. Check the "Safe Boot" options. Click on Apply and then OK. Reboot the computer. This will bring you in to a safemode startup. Repeat the above steps and uncheck "Safe Boot", hit apply and then OK and restart.
Give these a try and see if they fix your issue, hopefully one of them will.