Quick update - tried with no security at all on the 5ghz network to rule out password issues and the laptop still refused to connect.

Then about an hour after having the issue it realllly oddly has now picked up the network with the same SSID but added the number 2 on the end of it and connected with the same password it was refusing to use previously.The number 2 on the SSID is only showing on the system tray wireless SSD, in the properties of the wireless network it has the correct name without the 2.

All the other devices in the houses are connected with the correct SSID without the extra 2 at the end.

Something is really wrong with this Killer driver I think.

Me too.

Very disappointing that over 3 months since this topic was opened and not a single response from dell customer support.  Shows you how much Dell cares about their customers.

Now years after and no single response, very sad 

Have you went inside the device manager and then to the WiFi card and then clicked properties?

there should be a setting which allows frequency changes.

https://www.quora.com/How-do-you-manually-switch-to-5GHz-WiFi-on-Windows-10?share=1

Well it’s just a program issue then because all a WiFi card does is provide WiFi.

The signals would automatically change when the signal gets too far away to 2.4Ghz but when it gets closer it becomes 5Ghz.

It's extreeeeemely unlikely this is the router causing issues. Wifi communications are created to standard no matter what the type. IEEE 802.11. So no matter who provided your router they all fit in with the same standard. For reference mine was a BT Home Hub (5 I think).

A good test for anyone with the issue to rule this out in one hit would be go to a friends house and try there if they use a different router. But as I said I highly doubt this would be the cause, but stranger things have happened with IT!

So you didn’t use the device manager to manually disable 2.4Ghz and use the 5Ghz only?

Thanks.

But....

All a WiFi router does is provide WiFi to your house or building.

The actual ISP provided the Internet to the WiFi router to provide internet to you.

Just like my poor grandma who thought that buying a WiFi router means you get WiFi as soon as you turn it on.

5ghz has much more bandwidth available and is obviously preferred (unless distance is an issue for some in which case 2ghz might even be preferred).

A good laptop will switch between both frequencies based on connection quality. To ask customers to disable 5ghz entirely on a high end laptop rather than address the actual issue would be an extremely poor direction.

If the issues still exists for any customers then I think Dell need to get re-involved. Perhaps Dell should look at providing an alternative Wifi card if the issue can't be fixed.

Then comes the manually switch in the device manager.

Sometimes its the router, as it might have that device as logged in, and on your end its not so you're trying to login to the router that thinks your device is connected,and it has a error on your pc say you can not connect.

I'm not saying this is your problem, but there is a lot at work in the router, can create log in faults, this is why your ISP will tell you to turn your router on and off if you have a internet problem, same with wifi at times.

What kinda strange things?

Sorry just re-read your message and realise you meant the reverse! Nope I didn't try using 5ghz exclusively. 

Perhaps if someone else has the issue still they can try this.

I sold my Alienware laptop on in the end not purely because of this unresolved issue.. I agree it was pretty poor that we didn't get a response from Techsupport. I tried all sorts of different settings (and drivers) including changes within device manager (sleep settings etc).

I did also purchase a different brand of Wifi card to install but didn't use it. I did actually manage to stabilise the issue before I sold it on. But honestly I couldn't tell you how\why I got it working as I was just repeating steps I had already tried. What I do remember is that I installed the Killer software and messed about with that for ages!