MSIE can't connect

Windows XP Media Center Edition.

"Something happened" today and now her laptop cannot connect to the Internet
using a browser. MSIE 7 says page cannot be found. DL'ed Firefox, and same
thing (used another computer).

Computer is networked and CAN see the other computer and can transfer files.
Can send/receive POP3 email. Can ping yahoo. Using IP address for yahoo in
the browser says "page not found."

CAN access Internet via browser in safe mode. Using normal mode, even with
diagnostic startup selected, cannot access internet.

Generally use wireless (with weak signal) but also moved laptop to office
with wireless router for strong signal. Also connected via hardwire and
still same results (at that point had both wireless and hardwire active), no
browser Internet access.

Turned off firewall, no help. Had Norton 360 (not paid and thus not active)
installed, but we uninstalled it (even though it's no longer on the desktop
nor listed in Programs, it may not have completely uninstalled). No change.

Used the Reset button in Internet options|advanced to reset MSIE. No help.

Used System Restore to go back two days. No good either.

Where else to look?

Thx.


--
Bill