Hey, I'm writing this from Turkey so my English may not be perfect but I've bought the New Vegas for PC and I come home and put the disk in to the driver and then the window who asks what you wanna do next (you know wheter you want to start setup.exe or open the files) didn't pop up so I go to "my computer" and I tried to start it manually but thr computer said "D:\Setup.exe is not a valid Win32 application". Then the window popded out (the window I talked about before) but it didn't said anything about installing the game. It just asked me wheter I wanna play the musc files and open the pictures or not. The game is original so I didn't expected to face a trouble butthis happened. Oh and in "My Computer" it said the disk is full and it ha 6.27 Gb's of data but when I opened the files inside the disk I can see data hardly enough to fill 1 Gb. Please help me!

Be sure you understand that Official Support is separate. This forum is for gamers to exchange tech information in, not for official support. Fallout3 had a lot of bad trouble with optical drives and with the DVD encoding. It was very, VERY picky about what DVD drives it would work correctly on, and there were literally THOUSANDS of complaints that were for the most part ignored. I really hate anything to do with Steam, and stay as far away from it as possible, after the install. Your problem has a bit of the same feel to it as the case was for F3. In your case, I would go to the Official Support for my answers, but there's some likelihood that you have run into still another of the myriads of reasons that FNV is a failure compared to F3 ~~ more Steam foolishness.

Data on disc is compressed. It will expand when installed. I think the requirements to install the game is 10GB of free hard drive space. Make sure you have that available.

P.S. If space isn't the problem, some computer and graphic card info/specs would be helpful for anyone to be able to help you.