I just switched to AT&T U-Verse for my internet, and they provided me with the router and everything needed for wireless internet. My work computer, running Vista, connects with no problems at all, just type in the password and go. My iPhone also connects with no problem once the password it typed in. I tried to connect my PC running 7 wirelessly, and an invalid IP Address message comes up. I tried connecting it to the router with an ethernet wire, and the same message came up. Also, it says that I'm connected to an "Unidentified Network." I've connected my PC to many different wifi connections over the last couple of years, and this is the first time I've ever had this problem. I've gone from school, my parents, coffee shops, even another house that was using AT&T U-Verse, never with any problems.
Neither my work laptop or my iPhone are having problems, so I can only assume it's something with Windows 7. I know there are solutions on this forum, but I couldn't really understand much of them. I'm not exactly computer savvy, but I do know a little.