Dell laptop lost wifi

hello there guys
i'm having a very annoying problem with my dell 3521 laptop
a few days ago suddenly wifi stopped working! i can't connect to any wifi, other devices can

what i tried so far to solve this problem:
1- forget saved networks, try to connect again, nothing
2- cmd,
ipconfig /release
ipconfig /renew
ipconfig /flushdns
netsh winsock reset
netsh int ip reset

didn't work

3- i tried usb wireless card -was also working fine before-, tried to connect to any wifi, same issue, didn't work
4- uninstalled wireless driver, restart, reinstall, try to connect to any wifi, still nothing
5- updated wireless drivers, tried again, nothing
6- did a system restore to a time when wifi was working fine, still can't connect to any wifi!
7- disabled ipv6, didn't make any difference
8- i don't have an antivirus software that could be interfering with wifi or something & i disabled windows firewall, still nothing


what else can i do guys? what's causing this really really annoying problem?
please help me, i'm going insane trying to figure this out

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