Never RUN any constant anti-viruses like I do now in fear my PC will completely die meaning I got to break into my bank earlier than I planned too, but I have AVG, SAS & MBAM running and I regularly watch films through my 360 that I have stored on my TV and it says when I go to my Video Libary on the Xbox that a firewall is blocking the connection, what is lightly to be causin this, which software? Any help much appreciated, thanks in advance folks. Sounds like you are PAYING for antivirus... the only REASON to pay for it is if you are a commercial user.

What firewall programs do you have?
Are you behind a router?

What OPERATING system is your PC running?
Hi:

I had that problem before, my guess is that you're using WINDOWS firewall. What's you OS, XP or Vista?

While you answer that, you should know that in order to share media files from your PC to your XBOX 360, your firewall have to be configured to allow network sharing, don't worry is not that hard.

Here is really useful link I used the first time I setup my network sharing to my XBOX 360;

http://support.microsoft.com/kb/911728

Hope this will help!