Hi, first try the following to see if the issue actually isn't with the drive:

http://forums.xbox.com/xbox_forums/xbox_support/f/8/t/624.aspx

If nothing there works and since you've already opened your 360 you could try cleaning the drive's lens.

If that still doesn't solve the problem you could as a last resort tweak the Xbox 360 laser pot until it reads discs again. There are plenty of videos on YouTube showing how to do this. Some might recommend having a multimeter for this but as long as you adjust the pot in very tiny increments you should be fine without one.

Get a clue before making completely ignorant comments please.

You can change your drive no problem provided you swap it for the same model. Not difficult, you take the drive out look at the model (duhhhh) then buy one of that model.

You don't get banned for that and it's entierly undetectable.

Remarks like yours really rile me because you make people who are stupid believe you and come out with stupid remarks like you just have. If you have evidence to support your claim then I'm all ears.

Changing the DVD drive on an Xbox 360 is as easy as changing the DVD drive in your PC. Literally, it uses same SATA connector.

It goes like this...

Plug old broken drive in your PC (SATA port)

Download JungleFlasher and dump key (very easy with half an hours research on net, you will be able to dump key)

Download original firmware for drive you have, insert key you have dumped from your drive as well as serial data located physically on the old drive itself.

Plug in new drive, flash the firmware you have inserted key into.

Put back in Xbox 360.

I've done loads of Xbox 360s that have bad dvd drives for friends and over internet. Charge £10 to do it, I wouldn't be charging money if it was going to get you banned or I'd have people who aren't very happy making that unhappiness known to me!

Sorted.

The only thing that is detectable and could cause a ban is if you are flashing hacked firmware - even then you won't get banned as long as your backups are made properly and have correct size game partition, ss, dmi, pfi and video data partition.

This is what I would suggest.  If you have a PS3 then play that until Halo 4 comes out and then buy the bundle.  Unless, you have other 360 games that you really, really want to play now then I say buy a new one.  What model did you have?  An older one or slim?  If slim model, then just buy the 4G 360 and use the HD from the other one.  It would be cheaper that way.

I would buy a cheap used one to hold me over until the next xbox releases.

I just bought my fourth xbox after not having one for a year. Mostly because i need one for Halo 4. But then again, halo 4 on its own is enough reason for me to get an xbox. I dont expect others to feel the same way.

You're crazy if you're actually serious, lol.

I am in the opposite situation just losing my ps3 to the ylod. Not having makes me miss it a lot for the online free services believe it or not.

But as I continue to play Mass 3 I really realize it is practically the same console as the PS3. I am getting a PS3 though, because I have so many games to play on my ps3. Especially the Elder Scrolls 5: Skyrim and the coming downloadable content. So I am going to replace my PS3 even though I can easily slide with only the 360.
I would say reasons like your current 360 library and the future exclusives like halo 4 are plenty to justify the replacement if you have the means.

Without meaning to bait you, what did you think it was before if not practically the same console as the PS3?

Not bait at all, I do not hide my thoughts on consoles I own. I thought of it the same, the thing is I find that whether it was the 360 or the PS3 the longer I  played one over the other I preferred the one I played more at the time. I bought the PS3 as the prime console first so 360 was always for exclusives and as a backup. I have now needed twice. Even if I think there the same I still think as a consumer Sony serves me more. But if you have only one, they are pretty much the same. When it comes to making first party exclusives though I think Sony has done the consumers better with more variety, by far really. 

Very well layed out and I'm pretty much in the same boat as you, started with a 360 and then got a PS3 for the exclusives. Was it worth the money, likely not, but hey got it now and when I start playing a PS3 game like you, I get used to interface, the no nonsense OS and like it. Then if I play my 360 start to like the eye candy over time of the dashboard.

But yes, the exclusives for the PS3 are what make it shine as you say of course.

I was interested to hear your response because you have a sensible history here and I knew your opinion wouldn't be fueled with a bias, but was generally curious to hear what you thought "before". Thanks for explaining it and sounds quite similar to most people I speak to in the real world.