I have a Sony Vaio with the 'LAN-Express AS IEEE 802.11g PCI-E Adapter", which is an Atheros brand. I could use internet with my tablet, my roommate could connect too, just not with this laptop. I was able to get an IP address and proper gateway + DNS server IPs but it just wouldnt communicate. I tried updating the drivers via that Czech site and Windows said it already had the latest driver, so I didn't pursue that any further.
Assuming this may be an incompatibility problem with teh WPA2 encryption, I tried to connect to the router via my tabletand I found out it was a Linksys 2500 router. I couldnt get into the router because the landlord changed the passord, but I searched and found this site and it looks like this is a recurring problem with Atheros drivers for all of you. I revisited the driver update issue by deleting my network card and its associated drivers, and then forcing Windows to install off the downloaded drivers. I'm FINALLY connected now via my laptop. Hopefully this is helpful for others who run into the same trouble!