I was having bad CTD in fallout 3. Found this, tried it, haven't had a single crash since. Thought it might help some people out.
Fallout 3 does seem to have a conflict with FFDShow codecs. You have to either uninstall them from your system or add fallout3.exe to FFDShow audio and video decoders exceptions list. Although you may not know it, FFDShow codecs may be present on your system if you have installed codec packs such as CCCP (Combined Community Codec Pack).
How to add Fallout 3 to FFDShow decoder exceptions list
1. Launch the ffdshow video decoder configuration window. You may access this through the start menu. If you have installed any codec packs, check the start menu entries of those. If you can�t find it on the start menu, right click the ffdshow video decoder (red) icon that appears on the taskbar when a supported video file is playing, and select �ffdshow video decoder� option from the menu. ffdshow_icon
2. Tick the �Dont use ffdshow in� checkbox if not already checked
3. Press the edit button that is next to the text field. A new dialog box will pop up. Press the Add button. The �Add incompatible executable file� dialog box will be displayed. Browse to the Fallout 3 installation directory and locate fallout3.exe file. Select it and press open. Close all dialog boxes currently open by pressing ok.
(OR you can simply type fallout3.exe at the end of the text field next to �Dont use ffdshow in� checkbox)
4. Repeat steps 2-3 in ffdshow audio decoder configuration (the blue icon in taskbar) window as well. It is important that you add fallout3.exe to both ffdshow audio and video decoder�s expections list.
Funnily enough when i checked the exception list in ffdshow both my morrowwind and oblivion games were the only two in there? Maybe these games also have problems with ffdshow