This morning I bought the PC version of Fallout 3, GOTY edition. I've been playing Fallout 3 vanilla for awhile now and decided to purchase the game of the year edition for the DLC addons. However, when I first tried to make disc 2 run, it wouldn't.

I proceeded to restart my PC, still nothing.
I then uninstalled my older version of Fallout 3, popped in disc 1, installed fallout 3 again, and tried to install disc 2, nothing.
When I pop in disc 2, the disc scans for a long time before the scanning stops. It does not autorun and double clicking it will result in a freeze; the same happens if I choose to right click + explore and double click the setup.exe in the disc.

Thinking that there must be a problem with the disc, I run back to EB games and ask for a disc swap. I come back and try out the newly swapped disc, the same thing happens.
I doubt that it's my DVD rom, since I can run the first disc fine.

I believe it is a UAC problem. Try running the disc as the Administrator.

Having the exact same problem: No problems with disc 1, but disc 2 is totally unresponsive. Disabling autorun and double clicking setup.exe from explore did not work for me (they said it might take 10 minutes, but I've been waiting for nearly 30 minutes now).

Is this a problem with my disc? Do I need to keep waiting for setup.exe?

edit: should have mentioned that I also disabled UAC on my machine before reinstalling the 2nd time.

I had the same problem. What I ended up doing was just keep trying. I think in the end I hit explore and double-clicked the Fallout 3 DLC launch. I had to wait about 5 minutes before it started running.

How do you disable UAC again?

Also, i'm pretty sure that it's a problem with the disc, but not just yours specifically, it would seem.

Please use this thread, http://www.gamesas.com/bgsforums/index.php?showtopic=1047568, there is a way to get this work in there.