We are using a peer-to-peer network and have shared the internet
connection yet some of the computers can not get certain website(eg
google.com; usps.com and various others). We had a dsl router and was
told that was the problem so i got another dsl router and same
problem. I now have my dsl modem connected directly to my network hub.
Same problem. We have windows xp pro

Hi:
  I think this might be your problem.  When I read your question I
knew I had seen that answer before.

http://www.annoyances.org/exec/show/article04-107 

Note this is the solution only if your sharing the internet connection
using the built in "share the internet connection" that is in Windows
XP.

renvhoek

above solution of mtu changing did not work