For those of you who have windows 7 installed and keep
getting kicked by punkbuster from COD4 for "unknown windows API". I have a remedy for the problem.
start - run - services.msc
go down to PnkbstrA services
right click - properties
on the 2nd tab "Log on" you will see its set to local system account
beneath that is an empty check box "allow service to interact with desktop"
check that box, click apply.
now do the same for PnkbstrB service.
restart your system and give it a test.
It worked for me. was getting kicked every 20 seconds, and now
i havent had a single kick yet.