Fallout 3 on windows 10

Going back to Windows 7/8

you can try running it in compatability mode if windows 10 has that, still haven't got the go ahead to download it XD

Did you actually try to play it? or just read that you can't?

Maybe try A Tale of Two Wastelands, it puts 3 into the New Vegas engine which is a lot stabler. You need the GOTY/Ultimate editions of both games though.

I dunno if it'll work in 10 but its what I had to use to get 3 working in 7 and 8

It didn't work under my windows 7 either. This was what worked for me:
(Disclaimer: This will disable Steam's overlay and playtime counter)

    Right click on Fallout3.exe and select Properties.
    Click the 'Compatibility' tab.
    Check 'Disable Visual Themes'.
    Check 'Disable Desktop Composition'.
    Click Apply.
    Click OK and run Fallout3.exe.

Take a look at this guide here:
http://steamcommunity.com/sharedfiles/filedetails/?id=149946772