FYI. I had a problem with my TL-WN620G card and Windows 7 releases 7000, 7100 & 7127. The drivers
would install fine, however, Win 7 was unable to connect to the internet without me setting up my wireless connection.
After a reboot Win 7 would not connect unless I either reconnected the card or set the network connection up again. I have now resolved the issue by using the Atheros AR5005-UG drivers.
If anyone is having a similar issue I would suggest you try and find the chipset your wireless card is using and to try drivers from the chipset provider.