Install the Patches
The company has released new patches for improving the performance of Fallout 3, stopping it from crashing and freezing and removing bugs in it.
Modify an INI File
1. Open Computer.
2. Double click: C:\Program Files\Fallout 3
3. Open a file named fallout_default.ini
4. Look for the string named bUseThreadedAI=0
5. Replace 0 with 1
6. Insert an another line beneath the above, iNumHWThreads=2
7. Save the changes you have made and close the file. [Press Ctrl + S to save.]
Fix the Registry Errors
Invalid or improper information in the Windows Registry may cause Fallout 3 crashes in Windows. You need a best registry/system clean up software. The registry in Windows is an important component of the operating system which shall be free from hidden errors.clean with RegInOut Cleaner.
Lower the Settings
1. Open the game Fallout 3.
2. Click Options.
3. Click Low button in the Details frame from the Options dialog.
4. Click OK | OK.
Clear the Game Cache
Bad files in the cache may crash Fallout 3 due to problems retrieving the information.
To clear the cache, open Console by pressing ~, and type PCB and press ENTER key.
Update your Drivers
If you are running the game with out-of-date graphics and sound driver, then update these drivers now. To download latest updates for your drivers, visit the website of the driver's company.
Try DirectX 9 rather than Newest Versions
Some users reported that they were experiencing very few Fallout 3 crash when they downgraded to DirectX 9 from the newer versions of DirectX they were using.
Modify Audio Decoder Configuration
1. Click Start | All Programs.
2. Click FFDShow | Audio Decoder Configuration.
3. Click Info & Debug or DirectShow Control from the left hand side.
4. Check up the box named Don't use ffdshow from the right hand side.
5. In the textbox underneath, add the file fallout3.exe, when it lights up.
6. Click OK and restart Fallout 3 game
Update Microsoft.NET Framework
Download and install latest version of Microsoft.NET Framework from Microsoft Corporation's website.