Well I've spent the whole morning trying to figure this out.
Have installed a new modem and software, no change.
Have uninstalled Norton Internet Security, no change. So have reinstalled it again.
Phoned my ISP and they said possibly spyware was causing the problem, spent 20 squid buying a anti-spyware package and yes, it did find a hi-jacker threat (which was overlooked by both Adaware and Spybot) but even after removing that I still have the same problem of the internet connection freaking out every few minutes.
Phoned ISP back again and now they say there's a problem with their server and I should try again tomorrow. Tried to explain that the problem has not been just today but for the past few weeks. They say their problem has only been today but are not prepared to help until tomorrow.
I bet their problem was been for the past few weeks as well but they just don't want to admit it! Perhaps I should try another ISP, how easy is it to switch? I'd have to relocate my website as well which is hassle I don't really have time for.
Grrrrrr, computers! >:(