Question about flashing updates/roms

My phone appeared to have bricked on me yesterday (rezound) and when you open the hboot screen it checks whatever files. Apparently two of the 6 or 7 files says error that there is no image.

In some instructions on running ROMs they say to put the file into the root of the SD card. What exactly is the Root of the SD card? I placed the zip file right on the card without it being in a folder. Do I need to extract the files and put the files in a folder with the proper name? I'm a bit confused because I keep reading that the phone should recognize the PH98IMG.ZIP file but my phone isn't telling me anything.

FWIW it was never rooted, just a stock unit. VZW is sending me a replacement but the VZW person mentioned I could try to flash the software from the SD card in an attempt to restore the programming.

Dude if you get this figured out lemme know because I am trying to help my sis with her Rezound but I have a GNex and I don't know what's up. I had her move the zip to her sd card and boot into bootloader and her phone didn't do anything. I'm lost trying to help her.