How do I get ChromeOS back?

Hi!

On my Chromebook, I downloaded some firmware to modify the BIOS. I installed Linux, drivers had issues... So, I installed a Chromebook optimized Linux version, it was eh.
So, I wanted to redownload ChromeOS. At this point, ChromeOS was deleted, but I knew I'm able to get it back.. I re-enabled OS Verification, and think that removed SeaBIOS from my PC. I went to get a ChromeOS USB, plugged it in, and..! Nothing. Still, the "ChromeOS is missing or damaged!" screen. At this point, I'd be happy with another Linux distro, or the default ChromeOS.

(Holly cow, I said ChromeOS way to much.) (Is it possible to get SeaBIOS onto the Chromebook through the missing or damaged screen, also?)