Correct me if i am wrong but i did this try a fair few years ago. I had the same problem as you had and all i did was use some type of air compressor. (Tire Compressor) I blew all the dust out of my Xbox 360 without taking any casing off. Now that i look at it though, i was rather stupid but it did no harm and worked perfectly fine afterward. Just a gathering off dust.

Treyarched wrote The drives laser is dying. easy fix is to buy a replacement drive make sure it's the same make and model as your current one. When you have the replacement drive out take the board from the old one and move it to the replacement drive and fit it back in the console.

Pretty common for the lasers to die in the 360s and the issues you are having seem to point to that.

Yup, it's either your laser or spindle motor.

It's a laser issue people!

As I said before replace the laser or do the pout fix simple as that!!!

You are either getting the error known as "Open Tray Error" or there is something with your xbox inside that isnt reading the disc properly.

I had this same problem when Xbox first came out. We sent it down to Texas to get it fixed under warranty. Been perfectly fine ever since knock on wood

Probably just your disk tray or the laser.