Looking at other sites, it appears that the steps I followed probably left out the important part of rooting and installing the correct recovery.
Is there anything I can do? Sorry to take up your time because I got in above my head and made a stupid mistake.
EDIT: I do have a "jig" on the way to try to fix it that way.
So, I was following directions online to try to get 4.4 on my Galaxy S3 (t-mobile). Well, I should have double checked the steps with another website. It had me copy the FlashingDroid zip to my SD card, boot to recovery mode, wipe data, wipe cache, wipe dalvik. Then install from SD card and reboot. My phone now does not power on, including recovery mode or download mode.
Last edited by butch81385; 21st July 2014 at 08:06 AM.