my friends wii had this that i softmodded, resolved it by tweaking the laser pots. look for a tutorial on this forum or the net. if your not sure you can do it don't try as you will ruin your drive. it needs to be taken apart.......................sudeki300
Its the drive, I fixed the same problem just today
What you want to do is to take the wii apart, plug the drive out, disconnect everything that on the drive by ribbons, remove the black tape , take the metal clip off makig sure that you DONT bend it now, there are 2 holes, one with a screw and one with...basicly nothing, make sure you have the MULTIMETER within reach, turn the multimeter on to 2000 Ohms, place one end of the multimeter on the pin above the screw and the other on one of the below pins of the screw, this should show some numbers between 400 - 1000(mine was 950), turn the screw very little counterclockwise and see if the Ohms are 590-610, if not continue turning the screw very little.
Thats how i did it.
Edit: Find the multimeter at any DIY store if you dont have one Lended mine from school