Visual Composer not working

Hello,
There are several things that I need help with. Thank you so much for your time and expertise in these matters!
1) I have had many challenges over the last couple of months trying to get Visual Composer to work on a regular basis. It seems to work sometimes and then will stop all together. Can you please take a look and see what is going on?
2) I have been unable to update my Revolution Slider. Can you please do that for me without erasing the sliders I have saved?
3) I noticed that I have a “drop-in” advanced-cache.php plugin. I’m not sure if that is from you, or where it came from. If it is a good thing to activate, can you please activate it for me?
Thank you so much! I will send my site login info in a private msg.