Accidently installed 550 driver and my computer lags horribly. went back to the 535 and its still lagging with so many things gone wrong

[Aravisian]

@sambridges

Could you elaborate on this?

You can find this one asked a lot, since GDM3 is not very clear about how to switch Desktop Environments:

Zorin On Xorg

Its already there. At the login screen after you put in your user name click on the cog wheel in lower right corner. There you will see a choice that says "Zorin Desktop on Xorg". Click on that and enter your password.

If you do not see the gear icon/cog wheel, then select the option to login in as different user, then it should appear. After making your adjustments, then just login as your normal user.