WIFI stopped working on my Dell XPS 13 9343.
Windows trouble shooting says its a hardware problem.
Is there a way to do any check with Dell software, or should I simply try to replace the Wifi Card?
Generally hardware like wifi card does not go bad.
Power down your Dell and when powering up press [F12] and run the preboot diagnostics. If they pass the hardware should be good.
Are you running Windows 10 Version 1709? If so try the workaround here:
Windows FAQs and OEM Downloads