Indeed, there is no Linux support for the BCM43142. You can load the Windows driver; with Windows's Device Manager you can look which driver .inf file is used by the device, then boot Linux and go to the Windows partition > Windows/System32/DriverStore/FileRepository and copy the folder with the same .inf in its name to somewhere on your Linux system. Then you will be able to load the .inf file inside the folder using Windows Wireless Drivers.
If you use 32-bit Windows with 64-bit Linux on the same computer, or 64-bit Windows with 32-bit Linux, then you may need to get the driver from elsewhere - probably it can somehow be extracted from the Windows driver files from Broadcom's or Dell's website.
Registered Linux User #528502
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