try wiggling the cables to see if you get anything.... maybe bad cables or try another TV or set of cables
Edit: Isn't there a way to reset all settings (or maybe just the video ones) to their default? It seems like I remember reading about holding keys down while booting. Does Maintenance Mode do that?
try another TV
remove all usb and try to boot....
Boot up the Wii, and when you hear the System Menu music (resist the urge to smash your speakers ;)), hold Down on the D-pad and, while holding down, press RESET on the Wii. See if it boots up normally then.
Nope does not work
I dont think this will erase the memory on the wii but if it does (lol) is there anything that you wanted on the wii.... if not then try the things below!!
1. uplug the wii
2. flip it upside down on a flat surface
3. you will see a door and a little screw
4. inside you will find the BIOS/CMOS battery
5. take that out and let sit for 30sec...
6. put back and try to boot the wii