Strange Internet problem behind a Zonet ZSR0104DE

I've been having a odd issue: Every so often, all but a handful of sites (like google) "cannot be found" (more specifically, domain name cannot be resolved). This happens to everyone behind a router, especially in the evening.

Furthermore, according to the router logs, my own machine seems to be reconnecting to the router (sometimes preceded by a time out), yet none of the other two are doing this. It seems the each time it times out and reconnects to the router the problems are occurring.

At first, I thought it was just some DNS issue with my ISP, but this has occurred since last week and I'm not so sure what could be causing this; I don't fully understand networking. If it's somehow being caused by my LAN, what would be causing it? (it is onboard nForce)

Any ideas? :?

EDIT: On further reflection, the "login" records are likely from me going into the router panel to read the logs....not sure on time outs though.....