Open a command-prompt window (in XP or 2000, Start -> Run -> cmd; in ME or 9x, Start -> Run -> command).

Type in the following command:

ping cache1.ntli.net -t -l 1

That's a lower-case L after the second "-" symbol......that'll leave a continuous ping command running, which should give you line after line starting with "Reply from...". When your webpages stop working, check the command-prompt window, and make sure it still says the same. If it doesn't, and Kazaa is still working fine, then there's a DNS-issue with NTL's servers. Drop me a PM if this is the case, and I'll give you an alternative set to use, and show you how to change them...