Hi RI. I'm Greg, an installation specialist and 9 year Windows MVP here to help you.
I'll give you everything possible to try in order of priority so that hopefully something works. If you need help performing any steps I'll be standing by here to guide you:
Enable IPv6 in the network adapter settings: https://www.tenforums.com/tutorials/90033-enabl..
Run the fixit from https://support.microsoft.com/help/929852 (Re-enable IPv6 on all nontunnel interfaces) and reboot.
Which network icon is showing in System Tray: the Wireless waves or Ethernet TV with plug? Left click to see if any Networks show up to sign into.
If not right click the network icon in System Tray at bottom right end of task bar to Troubleshoot Problems.
Check that the wireless button on a laptop is toggled on. It may be a Function (Fn) key or it may be an actual switch on the side.
Try powering off modem, router and PC and then restarting in that order with 1 minute in between each.
Try all of these steps: https://support.microsoft.com/en-us/help/10741/..
https://www.kapilarya.com/how-to-reset-network-..
Update your network adapter drivers from the PC maker's Support Downloads web page using the full model number, HP Serial Number or Dell Service Tag on sticker. Compare the latest drivers available for download with the ones presently installed in Device Manager reached by right clicking the Start Menu. Make sure you have the latest BIOS or UEFI firmware, Chipset, Display (Video), Sound, USB3, Bluetooth, Network and all other drivers, or else download and install the latest now.
If you have the latest network driver then try on it's Driver tab also to Roll Back, or Uninstall and then restart PC to reinstall the driver. Try also all older drivers from Update Driver > Browse > Let Me Pick list working backwards.
Go to Settings > Network & Internet > WIfi > Manage Known Networks, highlight and remove the network having problems, restart PC to see if it shows up again.
Try plugging in by ethernet cable to the router to compare, then plug the ethernet cable into the modem (if separate) to see if this might be an issue with the router.
You also are entitled to Support from your internet provider to get online on all devices. This is always included in the monthly bill. If your router is less than a year old they will also Support getting it connected and optimized.
Another option is you could replace the wireless adapter with an inexpensive USB nano adapter like this one: https://www.amazon.com/dp/B06XSFPDFX/ref=asc_df..
Or you can use an Ethernet cable as necessary which should connect automatically.
if this was caused by Windows Updates then you can check which were installed at Settings>Update & Security>Windows Update under Installed Updates, then uninstall them from the link there, and hide with the Hide Updates tool downloaded from here: http://download.microsoft.com/download/f/2/2/f2..
You can also use System Restore to get before the problem began, then check for Updates with the Hide Update tool and hide them: http://home.bt.com/tech-gadgets/computing/how-t..
If this was caused by Version update then you can roll it back in Settings>Update & Security>Recovery and then hide it until it matures using the Hide Updates Tool downloaded from here: http://download.microsoft.com/download/f/2/2/f2..
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.
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