Well if you unlocked and rooted, you have root permissions... You need to back up your stock rom and flash a different one... If you have the One X(L) I'd suggest Nocturnal'd Dirty Rom with 4.2 Elements for a cm rom, ViperXL for a sense based rom
BUT FIRST: reboot to bootloader and see what hboot you have, I'm guessing its 1.14-- if it is, you must be in bootloader while using the toolkit>put rom you want to flash in the /data/kernels (extract the boot.img to this location). Make sure you have a copy of the same rom.zip that you are flashing on your phone as well (I usually keep it in the downloads folder on my phone).
Now when you have all of the above ready, you must go into recovery and Wipe system, factory reset, then reboot to bootloader
While in the bootloader menu, make sure it says "Fastboot USB" above the menu.
Now hit the flash button in the toolkit under "kernel>using this command selected"--- this will flash boot.img to the phone... This should be fairly quick, after it is done, in the toolkit select "reboot to recovery", as soon as you are in recovery go to Install, select your rom.zip and flash it... First reboot usually takes a little while, just wait. Once booted up, enjoy!
EDIT: this above instruction is if you have hboot 1.14... If you do not have that, and it's 1.09 or otherwise don't worry about using fastboot, you can install from recovery