Disc is unreadable

Some places offer a disc cleaning service that may work so you could look around your local area for a shop that offers that.

Other than that then you would need to buy another copy of the game.

You could borrow a copy of the game from your friend and installed it to your HDD. You will still need the original disc in your drive for the game to run.

Install the game. If it fails to install you need to get a new disc, or borrowing one from a friend to install that one. Disc 'cleaners' and 'repair services' just sand off a small layer of the plastic off of the disc. Considering how thin the discs are already (They're not the standard thickness. Just compare it to a DVD), cleaning or repairing a disc like this will damage it beyond use. Wipe the disc with a lint free cloth from the inner circle outward to the outer circle in a straight line. Repeat until you've covered the disc. Wiping in a circular motion will risk scratching the disc further.

Using a disc repair service does not damage the disc beyond use.

I have used this many times to repair discs that were unreadable & it has worked every time.

Obviously it depends on how damaged the disc is in the first place on wether it will work or not but in my experience it's never damaged a disc beyond use.

It's a risky thing to do, like I said, because of how it's done. Thinning a disc raises its own set of issues. However, if his disc only has minor cosmetic damage, it could be the center of the disc--which cannot be repaired. I have a brand new game disc that I recently opened (about a few weeks ago) of an old game. However since the quality of the plastic has degraded, the center of the disc isn't readable by the console, and that results in read errors despite the disc having literally no scratches on it. Scratches very rarely in themselves cause issues like this, unless there's a lot of them, or they're very deep.

Yeah dont have it resurfaced like Gamestop,or Walmart does cause you know NONE of their preowned stock works you just buy it for decaration... Oh btw dont buy those $7 jeans they only last a year on my landscaping job naw go buy the $70 jean they last forever an never get dirty......./.-