I wouldn't call it easy unless you already have SMD soldering experience and tools (or a friend/mercenary with them); it would also need being programmed with a backup that you most likely don't have (since you need a hardware programmer or homebrew, to create it, and it's now too late)
And of course, even if you had all the materials/tools/skills, it just doesn't pay (outside of the experience) to repair a $20 product... (that's the street value of a non-Gamecube Wii with all the basic accessories, including a wiimote/nunchuck)
That just means the Wii Menu won't try to load the mail database; if that was actually the only fault, you could delete it with a factory reset... but your other claims ("strange screen and not updating") suggest more problems