This is a really strange problem. My browsers will not connect but skype and aim work fine. This seems to happen on system startup and if the system goes into idle mode.
Basically after shutdown, reset or the system goes into idle mode. I have to disable my Local connection then repair it before my browsers will work... Interesting thing is that Skype and AIM both work fine...
I don't think this was happening until I installed cable dsl but who knows for sure I changed connectivity and computer at almost the same time... doesn't seem like its connectivity because skype and aim still work.