Dodgy Internet

I've got a problem with my internet and am hoping you guys can help.

Currently I cannot open my yahoo email and the google webpage from my computer. Whenever I try, it attempts for 5 minutes before giving the usual unable to connect to webpage error. I can access both pages from other computers and I can access everything else on Yahoo, such as the Yahoo homepage, Groups and their search engine as well as everything else on my favourites folder(except for the one below).

Also theres a forum I use, when I reply to a thread it shows what I've written, I go back to the main page and it hasn't been updated, I reply again and it shows my previous post. I've asked the moderators for that page and other users and they aren't getting that problem.

To try and fix the problem I've cleared my temporary internet files, my cookies, my systems temporary folder, my history. Run an spy-ware deletion programme, run a virus check and defragged my system. The problem is still there.

The problem is specific to those three sites and only on my system and nothing I do can fix it. Any ideas?

My IE is fully updated but thanks anyway.

My friend's told me how to solve it. I needed to power down my broadband box for 10 minutes and then restart the system and power up the broadband box again. Fixed it straight away.