Fallout 3 weird patch issue

On fallout 3, when on the menu page, and on version 1.00, when moving the cursor, it feels normal.

But when I update the game to install FO:OA, it feels "slippery". If you know what I mean. Also when im on my pop boy. Still slippery. No problems when i didnt patch it up.

Any ideas why this is causing it?

Also, when does it activate? I know brotherhood of steel contacts you. But I never went inside their head quarters yet.

like floaty and or some lag/delay to it?

if so, this may be caused by a mouse filter/smooth setting

oh. okay. ill try and find it in the options and disable it. Thanks.