Strange Problem

I noticed degradation in internet activity on my iMac just after update for Safari (4.1.1) on Tiger. I called my ISP to see if they were working on something, and asked the tech to verify my speed (speedtest.com). They were not changing anything, so I verified connections from Victoria to Vancouver. performance was good.

When I tried to go back to my homepage, Safari stalled "unale to connect to server". We unpluged modem, router, shut down re-started, without sucess.
We used "ping" to google and other know IPs and averaged 40ms. That confirmed the computer was connected to the internet. On my PC, no problems whatsoever, so th hardware is functioning.

Mac Firewall is turned off, and the iMac still ourld not function connected directly to the ISP modem. Ping, trace indicate hardawre is fine.

I managed to archive Safari, and re-install 4.0.5 which I downloaded to the PC on a flash drive and transferred to iMac. Still no joy.

Skype also would not work, nor would Firefox, so I tried Camino... no jooy there either.

I am really puzzled.

Does anyone have a solution or suggestion?

grampa