Note that this will only change the DNS for that particular PC.
yep knew how to do it in windows but question is does it in effect override the router setting or would it be better to change setting in router anyway so any devices connected use the same DNS.....
If the changes to DNS don't resolve this (no pun intended!) then running Wireshark: http://www.wireshark.org/ and getting the logs to us might help us identify an issue.
Thanks for that link. This worked a treat for me and has made a noticeable difference to browsing reliability and speed. Initially I just tried changing the DNS on my laptop and that helped so now I hope the whole household will benefit.