Well, where to begin... I started playing one day and all of the sudden as soon as the map starts up it takes me back to the server selection screen and says PnkBsterB Failed to handshake. I've tried updating PunkBuster and making a .bat file but nothing works.

The only thing I can think of is that your anti-virus program or firewall is blocking Punkbuster from connecting to the internet and checking your game. I know this may sound risky as your computer would be vulnerable to attack, but try disable your virus program and/or firewall. If that doesn't work then see if Punkbuster is on your firewall/anti-virus "blocked" list (Only if your virus program or firewall has one).

That's all I can think of for you, also this is in the wrong section.. thought I might point that out. Technical Advice & Tuts would be better for this kind of topic.

I had a similar problem with CoD4. What i had to do in the end was delete the punkbuster folder in the game and then reinstall. I think i also installed the punkbuster of Battlefield 2 into my CoD4 folder (which does not work) and then deleted it. So try deleting the folder and then reinstall.

That gives me 1 good session of playing. Is there a permanent solution?

Weird it was permanent for me. reinstall?

Hmmm lemme try rejoining.