I can get online w/ IE6, but not IE8

Hello,
We just got internet back at home again. When Time Warner set it up, my desktop is running IE6, our wireless laptop is running IE8 and Trend Micro. There are absolutely no problems with the laptop, but as soon as I upgrade to IE8 on the tower, I can no longer connect to the internet.
I did the run>cmd>ping thing, and got a response. Granted, my tower is old (12 years, still running XP and no plans to upgrade it), and I only have a 750 processor, but that shouldn't matter (I hope).
Why do I get the "page not found"? What am I missing? Oh- I also did the run>cmd>........release and reset sequences with no success.

Any ideas? Something must need to be reconfigured, but I don't know what.

Joyce aka sewmonster