Have your tried moving the network cables on the router and try different ports.
Power cycle your router to clear it of glitches.
Or try connecting the problem computer directly to you hi-speed internet connection and see if the problem goes away.
It could be the router.
Here's a very weird problem. Ready for it? well. I have a Linksys wireless router, with 2 desktop computers attached via ethernet cable, and 2 computers, (a laptop and a desktop) connected via wi-fi.
The desktop (an HP) running Windows XP and IE will not display the www.netflix.com website at all! while the others do. The second PC connected via ethernet is also a Sony Vaio also running Windows XP IE.
Here's where it gets bizzare! I deleted the cookies, temporary files, ran spyware software, registry software, firewall settings, I also checked network settings and they match to the Sony PC, and it just still won't show the netflix website! here's where I go crazy!
I downloaded firefox on the HP thinking that IE was somehow corrupt. And guess what? even firefox doesn't show it! I get the 404 error-webpage as I got with IE! webpage cannot be displayed. I even pinged netflix with BOTH pc's and they show the same IP number, and speed! I just don't know what the heck's going on! any ideas? Thanks in advance.