Hi Ahmad, welcome to the community 
"Network unclaimed" means: no driver available.
Broadcom is the manufacturer of your WiFi chipset.
BCM43142 is the model of your WiFi chipset.
You need to install drivers for this chipset.
So, this will probably solve your problem:
And if that doesn't work for you: Here is a link to some more information how to select, install, and download the right driver:
https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx
I hope this helps
Thanks for the post, it should help him. But there are other problems like he can't save/transfer files to a USB drive or login as sudo/root. He will have to figure out if it is software or hardware giving him problems.
Hi Jim,
You're right. I'm just trying to solve one problem at a time.
I am a bit hesitating to answer that because I don't know the answer:
I don't know if he has the copy issue running from the live installer or not.
I don't know if he did safe eject or not.
I don't even know if he was trying to write it to a exfat partition (which, if I remember correctly, also will not work without installing exfat tools)
He may even have been writing it to USB on a ext4 partition which will ofcourse not be recognized on his MS-windows driven PC
etc. etc. etc.
He doesn't see the letters of his password echoing '*' as some other systems do (linux doesn't) and therefore thinks it's broken. I assume he kind of gave up at that point. I concluded this because he wrote:
So I really have to think carefully how to approach this. I'm not as good as @ricmarques who is very precise, thorough, and meticulous and therefore can lead a blind man through a maze without even being present; a magical ability I don't have.
Your comment about checking the checksum was spot on. With this kind of shenenigans that would also be the first thing I would have checked.
Anyway, I think his choice to go for Linux Mint is a good one. For beginners it is just a little bit friendlier and small issues like this can be huge if you're just starting out with linux.
He says he will report back. Hopefully he does, it will help us all to help others in the future.
i got busy doing my university TMA i will reply later
for the bcm43142 linux driver
sudo apt install bcmwl-kernel-source
but first fix your sudo issue.
Hello, so i removed the hard drive of the laptop and format it in windows using cmd with the command \clean then \create partition primary,\assign.
after that i download ubuntu-mate-22.04.4-desktop-amd64.iso i did the checksum and all the code is the same as in the website, i burn it into the usb ,install it in the pc , this time i checked the option that said to install additional stuff with using Ethernet cable , i think the wifi driver is with the additional/optional ,so now i can find my wifi network and connect to it , BUT when i upload png file to usb and remove the USB and put it again an error "unable to muntin " not allowing me to use the USB i connect the usb to my main pc running in windows and did scan and the troubleshoot fix it but the png is deleted, connect it again to the linux laptop and it work. the problem of not being able to enter the password to confirm the admin in terminal still there , thanks for every thing ,i really like this OS
Since all actions to storage devices (like USB drives) are buffered, you must choose "safely remove or eject this device" before removing the USB device.
Alternatively you can choose "unmount this device" or issue a "sync" command.
If you don't do this, the USB device will likely end up in a undefined state.
MS-windows has buffering disabled for external storage devices to prevent exactly this scenario.
Be aware that MS-windows can not read any UNIX/Linux native filesystem (or any standardized filesystem for that matter) so you have to format your USB device according to something that MS-windows can understand. That means it must contain only one partition and it must be formatted as FAT32 , NTFS or (if you installed the exfat tools in linux) exFAT.
This is something I never encountered on any Linux install . Be aware though that, contrary to MS-windows, a password prompt in Linux never echoes anything you type to screen. So it might look as if it doesn't accept input, but actually it does.
To test this, you might want to give it a simple command like:
sudo echo hello
If this doesn't work, either your typed password is incorrect (password is case sensitive) or you might have a problem with the pluggable authentication module (PAM) which unfortunately I can not solve for you because I don't have the knowledge to do so.
One other thing: If you are on a laptop, make sure your numlock is off when typing, changing or creating your password.
A lot of laptops are missing a numeric keypad and overlay the numeric keys over the regular keys 7,8,9,0,u,i,o,p,j,k,l,; which will mask the original function of those keys. Therefore, make sure that the numlock is switched off.
This is something that happened once to me which resulted in 15 minutes painful troubleshooting before I discovered it. A true facepalm moment. 
Also be aware that the things I mentioned may or may not be applicable to your case. I am not really good in remote troubleshooting so these are just educated guesses.