Unusual Wireless Only Problem - Need Help!

I have the most unusual problem and I have no idea where to turn.

Recently, I changed name servers so I could build a new website. The name server changes have resolved.

While connected to the internet through my WiFi connection, the old website continues to display. If I turn of WiFi and attach to the internet with an ethernet cable, the new site displays. It is the same result in both FF & IE.

This morning, I have deleted all my cookies, temp files, cache and everything else multiple times, rebooted and the old site continues to come up on WiFi only. I have reset my modem and wireless router numerous times, to have the same problem.

When I am connected via ethernet cable, I am still accessing the internet through the wireless router.

I have gone to the command prompt and typed:

ipconfig /flushdns

... multiple times

This doppelganger version of the old website will not disappear on wireless, no matter what I've tried, which is impossible due to the fact that the old site has been taken down.

I've never had this experience before. I'm not technically inept but I am totally stumped.

I am running Windows Vista 32-bit with Service Pack 2
All updates are current
The Wireless adapter is an Intel Wireless WiFi Link 495AGN
The router, although I'm not certain it is suspect, is a Linksys WRT160N2 with the latest firmware update (7/1/2009)

Any ideas?