To be honest, download RSD_Lite 8 -> download 2.3.340 sbf -> enter bootloader bootup ,right click app "run as admin" (for rsd to discover phone) -> sbf and reinstall GB zip/wipe again.
If this doesn't do it for you, it may be something much deeper with the hardware itself.
If this doesn't do it for you, it may be something much deeper with the hardware itself.