If you don't plan on updating your Wii, then GeckoOS is a good choice to launch retail games.
You can also use some USBLoaders (neogamma, USBloaderGX, other?) with the "launch DVD" option.
If it's a burnt game, you can remove the update partition before burning it, using
WUM (Wii Update Manager) : download the "NO" firmware if you don't have it out of the box, load the iso, press "Brick Block" to path the update partition with an old update partition (an empty one in fact).
burn the iso, it won't ask for any update.
If you don't update your console, and try to play newer games, you may need to install the game's requested IOS first.
- GeckoOS can do that for you if you use the unpatched game/iso.
- you can open your game in wiiscrubber or Trucha sign, and extract the needed wad from the update partition. Use a wad manager to install them.
- Use NUSD or ModMii to download the needed wad and install them with a wad manager
- There's other way to extract wads too, but these 3 are the easiest.
If you don't have any problem with updating your Wii, just know that starting from 4.2 you can't launch imported region burnt games. (well, it was the case, I don't remember if it's still a problem), so updating to 4.1 is a good choice if you are still using your modchip as main source of playing backups.
Again, if you don't want to use your modchip or imported games, just follow any tutorial to update to 4.2 (
Xflak's ModMii or
xzxero's guide).
I personally used xzxero tutorial on 3 Wiis successfully (3.2, 3.3 and 4.3)