Re: halts after clicking 'New Game'
hmm, What firewall are you running?
Have you tried Verifying your cache?
Right Click on Sin
Verify Integrity of Game cache
If not can you paste your DXDIAG log
To create one
start / run / dxdiag
Click Save All Information, and copy and paste the log in to a reply.
I really think it is something to do with connecting to the Web.