Mine's on the fritz as well. Launch day Wii (November 19, 2006) and recently it's had trouble's booting up. I'll turn it on, and the start up screen boots up (Press A to Continue), but the Wii OS never appears and the screen stays black. Have to hold the power button on the console to actually turn it off.
Hopefully I can get it to work long enough so that I can transfer the files to Wii U...