I am connected to a wireless g router that used to work fine with my computer. All of a sudden it stopped loading plenty of websites. For example, it loads Mac Forums, google, yahoo, facebook.com ... but it won't load yahoo mail, ebay, flickr, and many many more.

I did not update my computer to 10.4.9 out of fear of what I read on these forums. I can ping the router just fine with a 1.4 ms time.

Any suggestions on how to troubleshoot??