How can I alter my Wifi password when I don't know what it is?

Q I would like to change the password that I’m required to type to get online after my PC has started up. There were instructions on how to do this supplied on CD by my internet service provider (ISP), Plusnet. Unfortunately, my son set everything up and he cannot remember what he did with this disc.

Is there any way around this problem? I have a Dell laptop running Windows 7 Home Premium that connects to the internet via a Wifi router.
Ken Sutton

A We think the password you are talking about is what Windows calls the ‘network security key’. This is distinct from the password required to log on to Windows, and different from the password your router will use to log on to Plusnet’s network.

It is possible to change the network security key on your computer but to do this you will need to edit the router’s settings. This isn’t difficult but, just to complicate matters, it requires yet another password – so that’s four distinct passwords.

Though most routers use default passwords that can be easily found online, it’s possible that your son changed it at the point of setup – we cannot know. More to the point, you didn’t tell us what router you have, so we are going to have to take a stab in the dark.

Fortunately, we do have some clues. You told us that the internet service provider is Plusnet. This ISP has for at least the past couple of years issued the same type of router to most of its customers – the Thomson 585.

If this is your router, to edit its settings first launch a web browser, type 192.168.1.254 into the Address or Location bar at the top and press Enter. The chances are that you will now be asked to enter a username and password to log in to the router – and if your son did change the password during setup, here’s where you may come unstuck (though we will explain the fix).

Otherwise, if you received the router after 24 November 2009, the username will be ‘admin’ and the password will be the serial number that’s printed on the sticker on the router’s underside.

If you received it between December 2008 and 23 November 2009, then the username is ‘Administrator’ and there is no password (so press Enter). If the router arrived between 27 November and 2 December 2008 then the username is again ‘Administrator’ and the password is the router’s serial number.

Assuming you manage to log in, then click Home Network on the left-hand side. Now click the WLAN: [PlusnetWireless] link (where [PlusnessWireless] is the name of your network, though it may not have been changed and may be ‘PlusnessWireless’).

Click the Configure link at the top right and at the bottom of the page you will see an Encryption Key field – this contains the password you use to log on to your Wifi network.

Click to place the text-editing cursor in the Encryption Key field, delete the text that’s already there, type your new password and click Apply.

If you failed to log in to the router in the first place, then you will need to perform what’s known as a hard reset to restore the device to its factory settings. You will then be able to log in using one of the three date-dependent methods outlined above.

To perform a hard reset you will need to insert a small pointed object such as a paperclip or a pen nib into pinhole at the back of the router while it is plugged into the mains and switched on.

Keep it held in until the power light turns red (which should happen after a few seconds), then remove the pointy object. After a few more seconds, the power light on the router should once more turn green. This means it has reverted to its factory settings.