Try a different browser like Opera and see if it exhibits the same problem.
If the emulators on the Dlink site are exhibiting the same thing, theres something going on probably on the PCs or the router thats blocking internet data. I use the emulators all the time and don't see this problem.
Turn off all anti virus and firewall programs on PCs while testing.
Try a factory reset of the router.
What Hardware version is your router? Look at sticker under router.