How to fix http 404 error?

How can I fix the HTTP 404 error PLZZ HELP ME!!!?

• I've been trying for TWELVE HOURS to fix!!!!! No lie or exaggeration!! PLEASE PLEASE HELP!!!! I cant connect to google, runescape, or youtube, and a few other ones.. I've tried EVERYTHING!! dont tell me to do what I already tried... and dont tell me what the error is.. tell me how to fix it.. pleasseee :( I've tried: Registry scanning and repaired. Several antivirus scans from different software. IP changing. Clearing cookies and temporary internet files. Downloaded a few new browsers. Restarted my computer serveral times. Went to run>cmd>ipconfig /release>ipconfig /renew Restarted my router and a few other things that i forgot.. it is not my internet connection.. I am connected and have perfect connection.. these websites were working fine yesterday but i dont know what happened.. and dont tell me that the website must not be available or anything like that.. it IS available because its working on every other computer! I am not IP banned or anything like that! there is NO firewall not letting me go to these sites. The site is NOT blocked on any of my browsers. PLEASE PLEASE PLEASE HELP ME!!!! I can't format my computer either because i dont have my disk with me! PLZZZ help!!!! You have no idea how gratefull I would be if you helped me fix it...

• Answer:

  You didn't include what operating system you're running, as far as I can see. You could try running the command line (Start | Run... | 'cmd' in Windows XP), ping one of the web sites you're having trouble with, and type the ip directly into the browser. If this works, then it is the DNS lookup that is failing, for some reason (that's traffic on port 53, usually). If you've set DNSes specifically in your computer, try setting them to automatic (so that your ISP can provide them), and if you haven't set DNSes, check to see if your ISP suggest specific DNSes.