Wi Fi not connecting to plusnet router

[#1]

Ok I’m not a Rooky when it comes to this stuff, here goes. My partners laptop after many years use has crashed and burned. She has used it on Wi-Fi in the present location for this length of time. We have just purchased a desk too to replace it with a usb Wi-Fi unit. Bearing in mind Wi-Fi has always worked in this location. When I search for Wi-Fi routers it comes up with three, plusnet (strongest) sky no1 and sky no2 , I presume the two sky ones are near neigbours. When I click on the sky routers it immediately as expected comes up asking for the router password , which of course we don’t have . When I click on the plusnet one it seems to do a search but Never asks for the password, it just says can not connect , or words to that effect. Although it’s the strongest Wi-Fi I have tried moving the computer to within feet of the router. ALL other devices connected to this router works fine with a download speed of 25mps.
What am I doing wrong
Rog Trumpet.

[#2 · Accepted solution]

@Trumpet1 Is the Plusnet signal yours?

[#3]

Yes it IS my router proved by switch it off and watching it disappear from screen. Download speed on router is at present 25mps , all other devices working fine.

[#4]

Moderators Note

This topic has been moved from Broadband to My Router

[#5]

@Trumpet1 That does not make sense - can you provide a screenshot  of that actual message, please. It may just be possible the Wi-Fi adapter you have is not compatible - which will possibly need input from other Community members, although I'll try my best. What make/model of adapter?

[#6]

How do I attach two screen shots, they are jpg but can’t see how to attach

[#7]

Click the icon to the right of the 'smiley' one and follow instructions. If you are using a tablet/phone, you will need to request the 'desktop' version of this site for it to work.

[#8]

What is the "usb WiFi unit" - is it a recent purchase?

Which router are you using?

If I had to guess here, this might be an old usb WiFi card which only supports a or b mode WiFi whilst the router is configured in n mode only.  In such circumstances, the PC will see the WiFi SSID but not be able to establish a connection.

I could be completely wrong...

[#9]

A new usb wi Fi dongle received this morning cured the problem

[#10]

In that case, mode incompatibility would be the most likely culprit. Legacy a, b and g modes do not work with some modern routers. The devices can see the WiFi SSID but cannot negotiate a connection.

[#11]

Yep a new usb Wi-Fi dongle cured this , thanks everyone