If your mouse feels off or accelerated do this:
Press Windows + R, type %localappdata% and hit Enter.
Navigate to:
Plutonium > storage > t5 > players
(T5 is for Black Ops 1, T6 is for Black Ops 2...)
Open the file config.cfg using Notepad.
Look for the line:
seta raw_input "0"
and change it to:
seta raw_input "1"
Save the file and close it.
This enables raw mouse input and completely disables any hidden acceleration as long as mouse acceleration is disabled in Windows.