My xbox 360 keeps saying disc is unreadable!

If you get the error with just one game, but not others, unfortunately it is likely damage to the disc. If it is under warranty, or if you bought it at a return-friendly place, maybe you can get a replacement. If the system is giving you this error with several games, it is likely the disc reader in your Xbox. The Xbox 360 has a well-known issue with DVD drive failure over time. If your system is still under warranty, or sometimes even if not (because this was such a big problem for Xbox), Microsoft may repair it. Try calling them and patiently discussing it. If it is not under warranty, and you are good with repair work, try this: http://hardandsoftgaming.wordpress.com/2011/03/12/replacing-a-faulty-xbox-360-dvd-drive-firmware-flash-or-circuit-board-transplant/

sounds like the fifa 13 is scratchd 1 go to bathroom 2 use soap 3 dry the disc 4 insert disc into the drive and restart the console 6 if this dosent work call xbox they will give support

If the guitar hero is new, I recommend taking it to where you purchased it and having it replaced. Tell them it will not play on your brand new XBox. Sometimes, rarely, you can get a defective disc.
Hopefully that will fix your problem. If not, you might look into returning the system for a new one.

Then your disk wont work so try to take it back to the store you bought it from and get a replacement.

if this is for just the one game there is an issue with the game it wasnt formated properly i had this same problem with NHL11 there is no fix besides replacing it

"A temporary solution" If u got the new xbox experience and enough HDD space, install game to HDD and then play from HDD. You'll probably have to send back to Microsoft eventually. Though make sure its only COD4 thats giving trouble, buy some disc cleaner and see if that helps

Your laser lens is going out and needs replacement. Either replace the whole drive (but switch out your old circuit board into the new drive) or buy a new laser and install it in (model number is etched into the bottom of the laser).

You have to switch your old board out of the old drive into the new due to Microsoft having "Keys" locked into each drive so you cant fix your system easily. So remember to keep the boards seperate and switch the old board into the new drive and install the new drice... should fix it nicely.

http://serviceman.site88.net/index_files/GameConsoles.htm

theres a known problem with the hitashi dvd drive in the xbox 360.
the only solution to this is a home repair job, look up on youtube on how to do this, although this isnt recommended as it voids warranty.
so the best way is definitely just to ring microsoft and send ur console in for repair.

Here you go hopefully it'll work! http://support.microsoft.com/kb/909819