Can not find disk

Here is what I did and it has worked ever since.
I'm not a DVD tech, but I'm a career printer technician so I understand electro-mechanical devices.
Symptom: "Loading" for about two minutes before "no disc"
This adjustment is very delicate. Be gentle and patient.
The issue (on mine at least) was that the (I don't know what to call it) "platform" that the dvd rides on had slid down the shaft and was rubbing aganst the motor housing. This was keeping the DVD from spinning up to the correct speed. I VERY GENTLY took a small prying device (the blade of my pocket knife) and pryed this "platform" back up the shaft just a hair. You pry a bit, then you turn it half way around and pry again, and you keep this up for four or five times. (Did I mention GENTLY?) It doesn't have to go far, just a fraction of a millimeter. Just enought to keep it from rubbing the motor housing.
It's not a permanent fix because after a while it will get worked back down the shaft by that monster weight that rides on top of the dvd. Not real sure why that thing is even there, but I left mine in. Some have mentioned taking them out. As a more permanent solution, I'm thinking about putting a micro drop of superglue on the end of that shaft to stop the slide.
I hope this helps!
Dave
Fairway Laptop Service
Bentonville, Arkansas - Home of Wal-Mart!