Hello Sara,
Again, if I reinstall everything will I lose what I have done. I don't back my site up because it is held by a domain. Not sure how I would even back it up. If someone can walk me thru it and then tell me how to upload the files I created I would be willing to try.
By updating HikaShop you won't loose any information. It will just update the files and add new columns in the database if required.
Your views overrides, css overrides, language, configuration, orders, products will stay intact.
But careful if you have modified
directly an HikaShop file and you didn't use the backend interface for that....
Note that making a backup is always a good security.