It's OK. It happens, man. Just follow the steps below:
1) Boot to recovery by pulling out the battery and replacing it, putting the phone back together then pressing and holding the Home key, Volume Down, and then power at the same time. Your recovery will come up. quickly, then let go.
2) Plug your phone into a computer and go to mounts (or Partition Management if your in certain recoveries) and select "Mount USB Mass Storage" or something similar. It'll be obvious. You should see your SD card pop up on your computer as though you just plugged in a flash drive.
3) Re-download the ROM and move a new copy of it to your SD card. Then, un-mount the Mass Storage from your phone (There should be just one option on the phone).
4) Go into your "Partition Management" or "Mounts" screen and format your system, cache, data, and dalvik cache partitions. DO NOT FORMAT SD. You can do it a few times, but once is generally enough.
5) Go into your "Install" or "Flash" menu, whichever lets you flash ROMS and flash the ROM you just put on your phone. This will take a moment, probably like 2 minutes.
5.5) Flash GApps if it's not stock based. BobZHome's roms are CM based, so you need GApps.
6) Reboot into your ROM and wait. It may take as long as 10 minutes to load the first time. Don't plug your phone into the wall or a computer until after the ROM loads.
7)???
8) Profit.