Can see wireless networks but can't connect to them

Try this
1. Click Start
2. Type in CMD into the search bar
3. Right click on CMD in the start menu and select "Run as Administrator"
4. Type this command in: netsh winsock reset
5. Reboot the computer and check connectivity
6. If you're still having problems, check out this Microsoft link:
http://support.microsoft.com/kb/299357
Best to get antivirus once you get connected, AVG Free would do. If you are not going to renew your Norton subscription you're as well removing it (Uninstall a Program in Control Panel)

[Solved] i was lucky enough we had two spare laptops of the same brand, dell latitude E6420, so what i did was i replaced wireless adapter and connected with another computer,after that test it was still not working, then after that i become sure that the problem is hardware, it's not related to OS, or driver, i have already done all these tests for almost 3 days, i searched lots of forums, i believe you also need to do some tests, until you'll be sure that you're last chance is to test hardware, that would surely be replacement for your wireless adapter........... best regards, Sanaan Barzinji Erbil, Iraq