Vista & wifi - Can see wireless networks but can't connect to them!

I have recently bought the new Dell Inspiron 1520 which have installed Vista Home Premium and have Intel AGN 4965 card. All was going well But after few days I found that I cannot connect any wireless network that my card sees. I can see there are four wifi network in which one is mine. I have WAP security on and I cannot connect to any of the nonsecure networks. When I try to connect it then it prompts me for password and it accept the password but it is still not able to connect. I have never seen such issue before. Please help.

In such condition you should try to connect having the laptop which is close to the router. You just have to do the initial connection and once you are done with that then you will not have to close it anymore. This is just a suggestion and I hope this will help you. You can try other solutions which you know or the one you may get after my post.

You can try the above solution and if that does not work then you can go to the 'Manage wireless networks which uses the Wireless Network Connection. In that you have to remove your existing SSID network. After that REDO your SSID information after clicking on the add button. While choosing your security you have to make sure that you are using 'WPA- Personal' and NOT 'WPA2-Personal' and your firewall is also off. You have to uninstall the Norton antivirus if you are using that and once you are done with the connection then you can again install it.

You will find the advance wireless setting which you will find at the bottom of the page. When you open this section then you will find the box for "Enable SSID Broadcast". You should make sure that it is checked and if it is not checked then you should make it checked. This helped me when I was getting the issue. You should also try this. I hope this will help you too.

I think that you have to perform hard reset to your router and this will let your router to the default factory settings. I dont know the exact procedure to do that therefore I am not mentioning anything here. You can see the manual for your router and I am sure there will be a section for doing hard reset. In most of the cases I found that resetting it to factory setting solves the issue.

If you do not have SP2 then you will not be able to connect with PSK. You should try to remove the connection from Wifi using the advance settings and after doing that you have to go back and there you have to set it up as preferred connection with the WPA-PSK key. After doing all that plug it in the correct key which is case specific.

As you told that you bought it new. So I think that it is still under warranty. First of all you should call the dell support for the issue and ask them for the problem you are getting. They know each and every possible problem that can happen to their laptop because they solves several such problems in a day and they will provide you the instruction that exactly what you have to do.