[SOLVED] One machine blocks wireless on another?

[paulwesterman]

I have a work laptop (Dell Lat 7280 Win7) and it blocks the wireless network on my home PC (Dell XPS 8900 Win10).
The PC can be connected just fine but as soon as I start the laptop the network drops off the PC (i.e. the wireless network is no longer available in the list of connections).
When the laptop is off, PC works fine. Another Dell Win10 laptop (E6230) on the same desk, works fine. Also phones, iPads and other things all around the house have no problems.
I've tried updating the wireless driver on the XPS. When I look at the router config it says the XPS is connected and has an IP so it seems to have DHCP'd it but the PC can't see the network?
This is on Virgin Media cable in the UK. I'm sure I'm missing something obvious... thanks guys

 

[Ralston18]

My thought is a duplicate IP address.

With the work laptop off of the network, run "ipconfig /all" (without quotes) on the home PC. Check the home PC's assigned IP address and subnet mask.

Then connect the work laptop and likewise run "ipconfig /all" on the work laptop.

And on both computers, again at the command prompt, run "arp -a".

Look for different Physical Addresses with the same IP address.