I'm Greg, an installation specialist and 8 year Windows MVP, here to help you.
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 updating the Network adapter driver from the PC's Support Downloads webpage. http://answers.microsoft.com/en-us/windows/wiki...
If that doesn't help try Rolling back and then Uninstalling the Network adapter driver in Device Manager. Right click Start to open Device Manager, choose the Network adapter you're using, on Driver tab choose Roll back, restart PC. If that doesn't help ry Uninstall, restart to reinstall.
If this was caused by April Version 1803 update can roll back Version 1803 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...
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...
Try all of these steps: https://support.microsoft.com/en-us/help/10741/...
Go over this checklist to make sure the install is set up correctly, optimized for best performance, and any needed repairs get done: http://answers.microsoft.com/en-us/windows/wiki...
Start with Step 4 to turn off Startup freeloaders which can conflict and cause issues, then Step 7 to check for infection the most thorough way, then step 10 to check for damaged System Files. Then continue with the other steps to go over your install most thoroughly.
If nothing else helps then run a Repair Install by installing the Media Creation Tool and choosing from it to Upgrade Now. This solves many problems and will also bring it up to the latest version which you need anyway and by the most stable method. http://windows.microsoft.com/en-us/windows-10/m...
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.
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...
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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Standard Disclaimer: There are links to non-Microsoft websites. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.