Do you want to go back to having all of the original files?
To go back to the original files, just copy+paste the backup back into the '/main' folder.
But I don't want to remove texture hack. I only want to put original trees and fps lower things..
Well, if you used the version with the auto-installer, put the back-up back into the '/main' folder, then go back into the auto-installer and choose only the features you want.
With the version without the auto-installer, just put the back-up back into the '/main' folder, then go back into the texture hack folder and put only the features you want into the specified *.iwd file.