Well DON'T update. If you update to 4.3 you cant use SD card based exploits, and because the games aren't loading in your disc drive, then that would mean there is no disc/DVD exploit avaliable, which in return = broken wii (without NAND programming)
You may be able to run bannerbomb if you're system menu version is on 4.0 - 4.2. I am pretty confident that this wii can be fixed. I will wait until "Professional" comes along, as I don't have the files needed.