What's wrong with my setup? I can't go anywhere...

I have a Asus P5W deluxe running XP pro with service pack 2 and have tried to acees 2 wireless networks, a coffee shop and a library, both with in a block. I get a decent signal and connect but when I open my browser I don't go anywhere....

Both connections are unsecured and I get decent signal strength due to my antenna being out the 2nd story window. The same thing happens with the on-board wi-fi on the ASUS or my SMC USB dongle with a USB extender cable to get it out the window.

I am kinda new to this stuff and this was my first home-built computer. After building it I had a local, respected coputer shop give it a once over and they gave it a go. Everything works great but this.... :?

Any help guys? I'd read more of the forums but I had to go to my parents house and use their lousy 40k dialup on a computer than spontaniously shuts off....Doesn't do alot for your demeanor or patience.....

Thanks,
Bryan