I bought the FO3 GOTY off of Steam and, just as the title says, I'm getting an APPCRASH right when I start. I know it's not a requirements thing (HD 5870, 4gb RAM, etc.) and I tried the processor fix for quad cores.

However, I believe the problem is related to an error I got while Steam installed the .NET Framework 3.0.

An error like:

"You must use 'Turn Windows features on or off' in the Control Panel to install or configure"

But there, I see the .NET Framework checked off.

What should I do? Any information you guys would like? I have the K-Lite codecs installed as well, so I don't think it's that. I'm almost certain it's this .NET Framework thing but I have no idea how to go about fixing it.

Thanks a lot for any help, I appreciate it.