When you say you have checked the Windows* Update Log for any driver update, are you reffering to the wireless adapter drivers or any update in general?
Is this issue happening only with this specific network or with any other you try to connect?
Is this network domestic or corporate? If it is corporate, you might want to check with your IT department for any changing in the network security settings.
Also, it is important to check the AP (Access Point) or modem/router if there was any updates that might be impacting as well.
Antivirus and Firewall configurations may as well affect detecting the networks around. Please, check those recommendations above let us know as soon as you can so we can see provide you the proper troubleshooting.
Thanks for the response.
The Windows update log shows no updates were applied on 26th April. However, on further investigation I noted that the log in the Lenovo System Update utility showed a Wireless LAN driver update (to 18.40.0) at 10:50 am BST. This would be about the time that my WiFi connectivity disappeared. I didn't realise that the Lenovo System Update had its own setting to automatically download and install driver updates, so I have now disabled that.
This issue is happening with ALL networks - there is no WiFi interface shown in Control Panel\Network and Internet\Network Connections. I cannot see any WiFi networks at all, either in the office or at home, by clicking on the network icon in the tray. Other laptops (one Acer and one Vaio) both work fine at home. Therefore this cannot be anything to do with network security settings or modem/router updates.
I've tried disabling firewall and anti-virus with no success.
The main issue I have is that I cannot remove the PROSet Wireless 18.40.0 software. If I go to Control Panel\Programs and Features and try to uninstall Intel PROSet Wireless it fails and gives me a vague message about 'A fatal error has occurred' that I need to resolve in order to uninstall, but it gives no indication or explanation of what the error is. How can I forcibly remove this package and ignore any errors that arise and try a completely clean driver install? Can I just delete a bunch of files and reboot?
The information about this error presented suggests the wireless adapter is OEM's (Original Equipment Manufacturer). That means that your computer manufacturer, in this case Lenovo*, is the proprietery of this driver version installed. That implies that Lenovo* might have implemented the wireless adapter by adding or removing features that are essential to system integrity.
We recommend to contact them first and informed them about this and see if they have a way to allow their system to uninstall the drivers so you can test our generic drivers. For your convenience, here is the link to our generic drivers: Intel® PROSet/Wireless Adapter for Windows* 8.1 - version 18.20.0
Please be aware that the drivers available in our download center for this Intel® Centrino® Advanced-N 6205 is Windows* 8.1 compliant and we have no version available for Windows® 10
We haven't heard from you in a while. We would like to know if you contacted Lenovo* in order to check about the issue and also check if you still need our assistance. We are looking forward to hearing from you soon.