For a long time my wii wouldn't read anything at all. It would take and eject discs, but the spindle motor failed to spin the disc, and the laser failed to read. I ended up disassembling my wii several times in attempt to fix it, replacing the motor first then the laser, but when both repairs failed I simply replaced the whole DVD drive which did the trick. I'm not sure what's wrong with yours, but that was my experience.
I don't even know how it happened; it was months ago when I was playing brawl online, about to load a match, when my wii greenscreen'd with an error message, and then total functional failure. I'm lucky I found a DVD drive online for cheap, about $24 if I remember.
My wii's been through hell and back, but I've kept it working. Thing's a trooper, I swear.
Does the Queen need to reassert her queenly dominance over such a foolish boy? Such insolence.