Why Wont A Download Open When I Try To On Macbook Air

Why Wont A Download Open When I Try To On Macbook AirWhy wont a download open when i try to on macbook air freezes
My wife has an eMAc that has developed a problem. Any time she tries to download a file from the web, absolutely nothing happens. This is true for both Firefox and Safari and applies to any type of file (picture, game etc.) On the other hand, updates from Apple download fine and my laptop downloads fine when plugged into her cable modem. She is running the latest version of OS X and the start of the problem does not seem to coincide with any new software being installed.
Any ideas as to what might be the cause?
Thanks
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Why Wont A Download Open When I Try To On Macbook Air Freezes

Why wont a download open when i try to on macbook air 13.3Why Wont A Download Open When I Try To On Macbook Air

Why Wont A Download Open When I Try To On Macbook Air Louder

Delete the app preference file. Plist files can become corrupt when a Mac shuts down or restarts unexpectedly or when an app freezes or crashes. As a result, the app may not open. When you delete a bad preference file, the Mac creates a new plist file that contains all the app's defaults automatically. Looking how to pair with my MacBook Air. In the Bluetooth section on the MacBook Air it does show the Buds while searching. I have also turned BlueTooth off then on, etc. But that doesn't acheive anything. I can't see any switch/button on the Buds or case to toogle identification. Previously, I have successfully paired my MacBook Air with my S10+.