I installed Fallout 3 the other day and happily unaware of the troubles having a windows 7 system can cause I launched the game.
Whenever I started a new game I was unable to get passed the loading screen without having the game crash to my desktop.
This I managed to fix by adding the d3d9.dll file and editing the ini. file in my games to the following:
bUseThreadedAI=0
iNumHWThreads=1

At first I was happy just being able to actually play this darn amazing game.
But lately it has started to freeze on me more frequently and the rest of my patience finally ran out, when the game decided to freeze every other minute, when roaming the houses in Minefield.

So my question is, how do I stop Fallout 3 from freezing?

Here’s some details on my system:
Operative system: Windows 7 Home Premium (64-bit)
Processor: Intel Corei5 2500

Number of cores: 4

Memory: 8 GB RAM
Graphics: ASUS GeForce GTX 560 Ti

Dedicated graphic memory: 1024 MB
DirectX-version: DirectX 10
Driver version (NVIDIA): 285.62

I can run Skyrim on the highest possible settings without trouble, so I doubt the problem is caused by my graphical card at least.
The game is patched to 1.7 and I’ve no mods installed, but since I own the GOTY edition I’ve installed the DLCs.

Let me know if the information I’ve provided isn’t sufficient.

It has been widely discussed that Fallout3 has a problem running form the Program Files folder on a hard drive. Since this is the default install location, no one changes it. There are two things you can do. Move the game by dragging and dropping it to a location outside the Program Files or uninstall/reinstall the game outside the Program Files. If you do a drag and drop, this may cause problems down the line if you decide to add more to the game. If you uninstall/reinstall the game, during installation there will be a window open that asks if you want to do a default install or custom install. Choose custom install and in the box type the path to the location you want to install the game. For example; When I did the install, I typed "C:\" and the install program did the rest. Creating a new folder on my hard drive labeled "Bethesda Softworks" with all the game files installed inside. This has saved by a lot of problems.

I don't believe that's the problem, since I've two harddisks in my system.
I've a SSD harddisk for the operative system (C:) and a normal one for files and programs (D:).
So before-handed I already installed Fallout 3 on a different location than normal.

I think the ini file change should be:
bUseThreadedAI=1
iNumHWThreads=2

At least that's what I did from reading other threads and haven't had any problems since (After 17 hours of gameplay).

@Retaf
It worked! Thanks a lot : D
I've been able to play the entire day without it freezing on me! Yay!
Now I can't wait for the NV ultimative edition!
However I haven't seem to detect any of my installed DLCs, but that'll be in another thread if it doesn't resolve itself.

Thanks everybody for the help!

Appeciate the thanx but many others posted that fix before me. They helped me really enjoy the game.

Not sure if this will help your DLC problem but when you first launch the launcher click on data in the menu and make sure all the boxes next to the DLC's are checked. Then when you start the game all the radio messages should appear.

I know, but you still helped by suggesting it C:

Not entirely sure how to make the first launching menu appear once I've already started the game once ><'

You might can do it from the game menu if "Downloads" is highlighted. If it's not or the DLC's aren't in there, then you'll need to goto where your came installed to. Default would be C:/programs files(x86)/fallout3 or something like that depending on whether you installed it elsewhere. Open that folder then double click "Fallout Launcher". I made that the shortcut on my desktop. A menu should come up with Play, Options, Data, Tech Support, etc on it. Data is where your DLC list is located. Make sure to chck the boxes for the ones you want included in the game. Then when you click play it will take you to the game.

It worked! Brilliant, I can't wait to play them!
Thank you!

And surprisingly enough it seems I've run out of issues xD ..Till next time~

Good deal. Enjoy the game.

Im curious what worked ... was it clicking Downloads or from finding the "Fallout Launcher.exe ???

Never mind ... a re-read tells me you found the "Fallout Launcher.exe"

Yes this is a source of many woe's for people. The game does not put a shortcut to it , and im guessing the steam app creates problems with its own launcher. And then GFWL creates problems with the saves.

Hi I am also experiencing freezing issues, with no luck getting the .ini fix to work for me. I've tried threads=2 and threads =1 and still i get freezes. I bought the game through steam today (GOTY edition). My computer: i7-2600k, radeon 6970, 8gb ram, plenty of HDD space....

what else can i do to remedy the freezing? i have klite installed but dont have any special configs set up...