Hi Alina. I'm Greg, 10 years awarded Windows MVP, here to help you.
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:
1) See if you can System Restore to a point before the problem started:
https://www.windowscentral.com/how-use-system-r...
System Restore is your first line of defense and can take you back to a point before a problem began like a time machine. If it doesn't help then you can undo it. Read about it first in the tutorial above and then try restoring to just before this started. If System Restore is not enabled on C drive do that now so it's available in the future.
If the problem repeats or System Restore doesn't work then check which Windows Updates were installed at Settings > Update & Security > Windows Updates > Update History, uninstall them there or System Restore again, then immediately check for and block the Updates with the Hide Updates tool explained here:
https://www.tenforums.com/tutorials/8280-hide-s...
2) Update your drivers and BIOS/UEFI firmware from PC or motherboard maker's Support Downloads web page, using the full model number, 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 button. 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.
Updating drivers from the Device Manager or Windows Update is rarely enough. The most basic thing we need to learn to maintain a PC is keep the latest manufacturer's drivers installed from their Support Downloads web page.
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.
3) 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.
4) 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.
5) Enable IPv6 in the network adapter settings:
https://www.tenforums.com/tutorials/90033-enabl...
6) Run the fixit from
https://support.microsoft.com/help/929852 (Re-enable IPv6 on all nontunnel interfaces) and reboot.
7) 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-...
8) Fix network connection issues in Windows:
https://support.microsoft.com/en-us/windows/fix...
9) 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.
10) 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.
11) 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.
12) 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.
13) Another option is you could replace the wireless adapter with an inexpensive USB nano adapter like one of these:
https://www.amazon.com/OURLiNK-600Mbps-Wireless...
https://www.amazon.com/dp/B07P5PRK7J
14) 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:
https://www.tomshardware.com/how-to/fix-windows...
I hope this helps. Feel free to ask any questions. Based on the results you post back I may have other suggestions if necessary.
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