What copy of FO3 are you using ? Disc or download Steam or other online retailer ?
What is the other game ?
GFWL was a p.i.t.a even before MS dropped it some years ago, but the GFWL setup on the games disc is out of date,
so if you have not already, try installing the version in the direct Steam link below.
I don't know why, but some games that used GFWL are worse that others, so even with that version of GFWL you may need
to use an xliveless fix (a hacked xlive.dll file) or the GFWL Disabler tool which can be found at the Nexus.
I don't have a link for the disabler, but you should be able to find your way to the mods section via their forum.
- If you are using the disc based version of the game read my second post --here-- for disc based fixes.
Also patch the game to at least v1.5 - Fallout 3 : Patches, Updates, Addons, Downloads (The Patches Scrolls)
.