Internet randomly times out on my computer but not on anyone elses?

I have BT HomeHub 2 with BT Broadband and I have already been through this with them and they can't find anything wrong with the connection at all. So it is prob something or some setting on my computer. I am using Vista Home Premium 32, and the problem has been happening for about 6months or so, it never did before but I can't think what changed. Basically I will be browsing the internet and then it will randomly disconnect, if I am opening another tab, changing website or just sat there doing nothing. It won't show it has been disconnected on the little global/computer on bottom right taskbar, but the webpage will come up on google chrome, or internet explorer or even firefox saying can not connect etc. And I have to wait about 30secs refresh the page and it loads again. It is starting to get annoying and I have no idea what is doing it. Any help would be great!