OK guys, I am back. I got a response from HTC customer service after searching for solutions and trying literally everything (including what HTC told me to do). If your phone gets stuck on the HERO logo after this last update, you can try what I did.
1. Go to
HTC Hero - ROM Upgrade for HTC Hero and download the RUU version of the software (2.73 - so yeah, it's 1.5 alright).
2. Boot your phone into the bootloader - hold down the VOLUME DOWN key and then press POWER (or hold it for a bit) for the phone to boot up. It will boot into the bootloader.
3. Press the BACK key to switch the phone to FASTBOOT mode.
4. Connect the USB cable. Drivers should get installed to your PC (check in Device Manager under Android Phone) and the FASTBOOT on the phone should change to FASTBOOT USB.
5. Run the .exe file from step #1 and follow the instructions. You should see the installation process on your phone.
NOTE: do this only if you can't start up your phone any other way as this downgrades the software AND wipes all your data!!!
EDIT #1: if you got this problem from updating to the latest update, DO NOT UPDATE AGAIN IF YOU GET YOUR HERO WORKING!
EDIT #2: if you get ERROR170 when trying to update the ROM, uninstall and reinstall HTC Sync.