1) Go to your hardrive
2) Go to games
3) click on left 4 dead
4) there has to be a folder or thing that says user settings erase that if you have more than one erase all of them.
5) Start up left 4 dead
6) go to solo and press play right when you start the game exit out
7) Go to your hardrive and then go to games
Now go to left 4 dead and transfer the new User settings to your hardrive.
9) Go to USBxplorer
10) Go to the user settings and extract them to your desktop
11) go to modio and then game mod tools
12) press load file and open the one on your desktop(user setting)
13) Then just modded how ever you want to
14) press rehash and resign
15) then go to USB xplorer
16) go to the user setting thing and press inject
17) inject the user settings on your desktop
1 now erase the old one
19 go back to your xbox and go to memory and then hardrive and then press clear cache.
20) now go to your usb and transfer the user settings to your hardrive
21) now start up left 4 dead
22) do not update it now go to solo and enjoy the mods

if this helped please give some rep+ you dont have to though