Dante

I have BF2142 installed on two different computers - a Windows XP and a Windows Vista computer. On the XP, if the process "PnkBstrA" isn't running, then the game won't work properly. When I join a server, within 5 minutes, I ger an erorr box that just says "Punkbuster" and I get booted form the server. On the Vista, the "PnkBstrA" isn't running at all, not even on startup. What should I do about this?