I think you should change the DNS server temporarlily and see if the issue still persists. I notice you are putting that off

(Any specific reason?)
Assuming you have double checked windows firewall settings and other neccessary things, and tried a final full reboot of router and PC, in your position, what I'd now be doing is putting my router back to factory defaults in case port forwarding has upset it.
Can you post the output of an IPconfig /all onto here?
I don't think this is a Zen problem because more people would be on here complaining about it, but I could, of course, be wrong, which would make everything above (bar first step potentially) redundant.
______________
Zen 8000 Active
Edited by Pipexer (Sun 18-Dec-11 01:00:29)