Either you have something dodgy on your PC which is blocking or redirecting the connection attempt, or the problem is with your internet connection.
It's unlikely to be browser specific.
Try opening a command prompt (on windows the easiest way is to press the "windows logo" + "R" keys on your keyboard, type in "cmd" and press enter) and then type in:
ping www.bay12forums.com
(and press enter).
It should quite quickly say something like:
Pinging www.bay12forums.com [97.107.128.126] with 32 bytes of data:
Reply from 97.107.128.126: bytes=32 time=97ms TTL=54
Reply from 97.107.128.126: bytes=32 time=97ms TTL=54
Reply from 97.107.128.126: bytes=32 time=97ms TTL=54
Reply from 97.107.128.126: bytes=32 time=97ms TTL=54
Ping statistics for 97.107.128.126:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 97ms, Maximum = 97ms, Average = 97ms
This should quickly confirm whether you have any connection to the forums at all or whether it is specific to loading web pages.
If it shows any/all as "lost" or "timed out" etc then you have an actual connection problem. If the IP address (string of 4 numbers at the start) is not 97.107.128.126, you have something interfering with the connection.
EDIT: I assume you can get to other sites?