Hi Tony -- Diden't leave a space between the ping command and IP addresses last time. Done this correctly now and results are :-
" ping transmit failed , error code 1231 "
packets sent = 4 ,received =0 , lost = 4 ( 100 % loss )
this happened for both the IP addresses
PC B works fine router ping time was less than 1 ms and 0% loss
and other address was average 50 ms and 0% loss
Yes I have re-booted several times.
Thanks Kelvin .............