Windows 7 computer can't connect to Wifi using any adapter

Solution 1:

It sound like you are using WPA-PSK, this is a known problem in Windows 7 with WPA-PSK. Please have a look at this.

OR Follows these steps (mentioned in URL): -

(A): -

Go into 'Power Options' (Control Panel - Power Options) Whichever plan you have chosen, click "Change plan settings" and the "Change advance power settings". Scroll down, if necessary, to "Wireless Adapter Settings" and click on the + to expand and see "Power Saving Mode". Click the + again to reveal the options for "On battery" and "Plugged in". For both "On battery" and "Plugged in", choose 'Maximum Performance'.

(B): -

Go to Control Panel -> Network and Sharing Center -> Manage wireless networks -> Right-click on the network you are trying to connect to which requires your login credentials -> Properties -> Security -> Advanced settings -> 802.1X settings -> Check 'Specify authentication mode' -> then select user authentication. Click 'ok' until you are back to the 'Manage Wireless Networks'.

Now try to reconnect to the wireless network. Windows should now ask you for login credentials and you should be able to successfully connect.