Comcast - websites having loading issues

Hello,

I have a rather strange issue that I have not been able to figure out on my own, so I'm hoping someone here might have the knowhow to help me identify the problem.

I have Comcast internet (which the techs all tell me is sending a great signal) and at it seems to randomly have an issue where it will just not load a page when I either click a link or type in an address.

Sometimes it will load normally, other times it will give me a Page Not Found style error.

Other times it will just crawl when loading media intensive sites (despite speedtest.net giving me fantastic speed results) and most of the images on the page will display as broken images. If I click to reload the page, 9/10, this fixes the problem.

Here is the weird twist. I've tried Firefox, IE8, and Chrome... all of them have this issue.

But Opera does not. Pages seem to load fine with Opera, and I have not yet gotten a Page Not Found error while using the browser.

Unfortunately, Opera is not ideal for me, nor is it compatible with a few services I need to make use of on a daily basis, so it's not a real solution to my problem.

Any ideas out there?