Welcome, Pegeta.
First off, in order for anyone to help you, you need to provide more info. Eg. How old is the Wii? Is it modded? If so, what method, loader, etc. This can happen with damaged discs or backup discs with incorrect region
Strictly speakding, it sounds like a hardware prob with the drive. There isn't a manual eject b/c Nintendo wants you to send it to them. Here's a post from a user on a another site who had some luck:
"THis is going to sound wonky, but it works for me.
Step 1) get an index card
Step 2) gently slide the index card in the cd slot while pressing the Eject button. the blue light should come on
Step 3)Once you get the blue light confirmation, slide the card in ever further. Hit the eject button once more and start to slowly remove the index card.
If all works well, the disk will come with it, or at least enough to where you can pull the disk out manually.
I found this out because the Wii I ordered was dropped by the shipper. Not wishing to send to Nintendo, I found a Chinese restaurant's ordering manual. I put that inside of my disk slot(because it is thin, and can not get lodged in the Wii itself) and pulled it out.
Works like a charm...if you don't want to wait around or anything.
I hope that helps.