Well unfortunately there is no magic solution.
First, try to play without any downloads at all to see if it is anything from your download causing this problem.
If without it your game runs fine. You will have to add batch of cc in your game to isolate the problem.
You can run the hack detection tool found at
http://www.simwardrobe.com in case it is a mod conflicting problem.
You can also check with the clean installer found at mts2 to check if nothing weird you are not aware about is in your downloads.
You could try also to update your video drivers, it might help.
As for no cook and server problem, you could try and delete the stove and restaurant podium on the lots they are not showing and replace them with new ones. If you are using cc one, maybe THEY are the problem.