internet connection stopped working on laptop

[#1]

yesterday 02feb one of my 3 computers running xp home stopped connecting to internet.
tried the following:
reboot
changed connection to router via ethernet and wireless can address router using either
pinged 212.58.241.131 (the bbc) ok but ping to bbc.co.uk no good
changed browsers firefox, safari & ie no joy
changed routers same symptoms
turned off firewall
I'm at a loss as something in my laptop is stopping 2 way coms but I cannot as yet find it
Help please

[#2]

Hi Drib.
As far as I can tell from that, it would appear to be a dns problem.
I would advise configuring TCP/Ip to use Plusnets DNS settings and that should resolve the problem for you.

[#3]

Thanks Keith but your techie that I spoke to yesterday 03 Feb was also baffled as that did not work either.  Resolved by me with System restore to go back 3 days.  I.m still baffled and would be grateful for any solution that could explain and perhaps be of use in future

[#4]

A computer virus corrupts DNS and/or inserts a proxy server (which is then taken offline).  Your security software removes the virus but does not correct the corrupt settings.  Then System Restore performs the necessary correction.