How old is your Harmony? There were some issues with Supercharger games on 7800s in early BIOS versions but these were fixed. If you have an old BIOS (I think 1.03 or earlier) you should update it.
I just got it for christmas. I have version 1.05 but before i put my new roms on i reformatted my sd card. Could that have something to do with it?
No, formatting the card wouldn't matter.
It could be that you have the PAL version of the game. That would explain why you hear the music but don't see anything on the screen, as some televisions will not display PAL games.
Either way, can you post the binary you're playing? I'd like to try it out on some of my consoles to see if I can replicate the issue.
its not a pal rom cause it plays just fine on my 2600
Can you post the binary or tell me where you found it? I have a number of 7800s (some with known problems with Supercharger games) and would like to test with the same binary.
This is my main one that has this problem