Need help with Fallout 3 on windows 7

try compatibility mode? never try this game on newer windows, so can't help much.

Set Windows Xp Sp3 compatibility for Fallout3.exe

ive tried but no good! man, this sucks!

Try this
http://forums.steampowered.com/forums/showthread.php?t=1328904

Fixes and things on this site will probably help.

nope! no good

Download the Large Address Aware Enabler for FO3 http://fallout3.nexusmods.com/mods/6510/?tab=2&navtag=%2Fajax%2Fmodfiles%2F%3Fid%3D6510&pUp=1
Follow the instructions from here http://www.youtube.com/watch?v=nMJLdWmHzOM
This should help reduce crashes, and will be useful if you decide to download a texture pack.

I found some fix somewhere... It was a DLL that disabled Steam for it, which means it won't log your time, and you don't need Steam to play it... Don't remember where it is though...

you have to edit the .ini file. Find the line bUseThreadedAI=0 change the 0 to and add this line below iNumHWThreads=2 if it still crashes change the 2 to a 1. Hope this works

Have a read here
http://www.reddit.com/r/Fallout/comments/1iaj6s/crashbug_fixes_for_every_fallout_game_for/

disable all but one cpu core -> profit

http://steamcommunity.com/app/22370/discussions/0/828937546147175081/

I had this exact issue and it was totally resolved by setting core affinity to 2 cores. You don't need to download anything or use a script to do this. Just run FO3 and go straight to the task manager. Right click Fallout 3 and choose 'Go To Process'. Right click the highlighted process and select 'Set Affinity...' and deselect all but two cores. I'm not sure if it matters which ones but I keep 0 and 1 selected. After this all the crashing I experienced in game completely stopped. For some reason now though, I still get crashing if I leave the game paused for more than a couple of minutes, I haven't been able to resolve this so if it happens to you just quicksave before you pause the game.

Good luck!

Thanks for the help and links guys, i got it to work!