Hey there,

Looks like you may have to reinstall Zen Cart.

You will spend more time messing around trying to find the problem than a reinstall would take.

Don't worry about it though as these things happen and it is a learning experience.

So you will need to connect to your web space and delete all the contents inside the shop folder.

When you reinstall it the next time.. make the minor changes like the banner then do a FULL back up.

Each time you make any significant changes or things that take time.. do another back up.

Ask your web host if they have back up software for their services which you have access to do yourself if you are unsure how to do this. AFTER reinstall you need to back up the shop folder AND the SQL database for the shop.