How can i fix the Battlefield Bad Company 2 sever disconnects?

I bought Battlefield bad company 2 off of steam, since i got it i have been able to play for 3-5 minutes before being disconnected. I opened the ports on my firewall, put the computer in DMZ, completely turned off my firewall. There is no UPnP setting on my router or a TCP timer. does anyone else have any other solutions?