Right-click the internet icon in the notification area, and click "Troubleshoot Problems". Windows will look for problems in your internet configuration, reset your network adapter (wireless card, in this case), and check other things.
Sometimes with a clean install, the internet can be a little flaky at first. Did you update your drivers like I said to do?
Well, wait a second. It looks like there are no Windows 7 drivers
for your particular model.
You may have to fight with it for a couple days until it works with no problems. Whenever I've used a new computer, the first few days are always hectic (install software, fix things that don't work, beat my head against the wall, etc.). You'll just have to be patient with it. I know that's hard to do with something as important as the internet, but don't give up on Windows 7 just because of the bugs you have to deal with when starting out. Everybody has some problems to start with, but 99% of the time, they do get resolved.