Cannot browse without using proxy

[OldandSlow]

Hi all, First post so be kind

I am a Virgin media(ex ntl) user connected via ethernet direct to 250 cable modem. before my troubles I had been using the same settings/ computer for some time without any trouble. I started to get serious connection problems with almost no service what so ever most of the time, back then an NTL advisor told me about proxy servers so I changed my settings and was trouble free. Every now and then I would try going back to normal direct settings but no connection at all. With VM now "stopping" their proxy server I need to get to the route of the problem. As I said alls well through a proxy but nothing direct. I can connect to https sites direct, I don't know if this gives any clues. All help appreciated thanks.

B.