OK - here is where I am... I looked at the connection logs from my servers to your connection...
Marc is right on - you have a bad config either in your home router or your Windows config (sorry - I don't know which, as you have a firewall in place in your circuit).
So - what's happening - is when you "Open" the site - one of your programmed DNS servers doesn't reply - so it tries to go look for the other... Before THAT can reply, your browser times out - throwing up that error "Not Found". I can't figure out if your ISP has Round-Robin configured correctly, but - there is no hand-off..?
Anyway - you can fix it - but, seeing your Avatar I'm not sure how far you want Marc and I to walk you through it??
John D.