Hi Lexie. I'm Greg, awarded MVP for eleven years, Volunteer Moderator, and Independent Advisor here to help you until this is resolved.
Try going into the Device Manager > Network adapters > Affected Adapter > Update driver > Automatic to scan the Windows Driver files, and if not then Update Driver > Browse > Let Me Pick to see if any older drivers are still installed to choose.
If this is a wireless adapter you need to download the driver for, then try plugging into the modem or router with an ethernet cable which should get you online to do this.
If not you'll need to borrow a PC or go to a Starbucks or internet cafe to download to a flash stick the driver from the PC or motherboard maker's Support Downloads webpage for your exact model, Serial Number of Dell Service tag. I can help you find this driver if you will give me one of those identifiers.
Once you have the driver installed, if the problem persists I'll give you everything that works to fix Wifi so that at least something will work. Even if you've already tried a step please try or check it again in sequence. If you need any assistance I'll be standing by here to help:
Update the rest of your drivers. 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.
Go to Device Manager > Network Adapters, select Wifi adapter, then Power Management tab, clear the check box to "Allow the computer to turn off the device to save energy." Then on the Advanced tab disable any energy-saving options.
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 explained here:
https://www.howtogeek.com/223864/how-to-uninsta...
You can also use System Restore to get before the problem began, then check for Updates with the Hide Update tool and hide them: https://www.windowscentral.com/how-use-system-r...
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.
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.
Right click the network icon in System Tray at bottom right end of task bar to Troubleshoot Problems.
Try all of these steps: https://www.kapilarya.com/how-to-reset-network-...
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.
Try powering off modem, router and PC and then restarting in that order with 1 minute in between each. You may need to reset your router or even optimize it following these steps:
https://www.lifewire.com/resetting-a-home-netwo...
https://www.pcmag.com/article/258865/how-to-set...
Your router manual is always available from the manufacturer's website for your exact model.
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/OURLiNK-600Mbps-Wireless...
If nothing else works then do a Repair Install, by installing Media Creation Tool, open tool and choose to Upgrade Now. This reinstalls Windows while keeping files, programs and most settings in place, and is also the most stable method to advance to the latest version. http://windows.microsoft.com/en-US/windows-10/m...
I hope this helps. Feel free to ask back any questions and keep me posted. If you will wait to choose if I resolved your problem, I will keep working with you until it's resolved.
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