One 'n a half years... ? You've got my sympathy, man. o_o
If it's not the cable or the TV, I'd come to the conclusion that your Wii is a different region than your TV (NTSC for the Americas, PAL for Europe, etc.) and thus incompatible, or your Wii's broken in some way. If you didn't get your TV/Wii from a different country from where you got your TV, it's definitely the fact the Wii is malfunctioning. I'd recommend contacting Nintendo for repairs ASAP if this is the case... I think you've waited long enough to get your Wii up and running again.