Windows 10: Product Key isn't working anymore

I purchased this laptopDell Inspiron with a pre-loaded windows 10 home Single Line version Recently My Windows got updated through Windows Update, and now it's popping this alert again and again. I tried to insert the old Product Key but it is denying stating "The Product Key you entered didn't work...."Images are attached below.I talked to the support team as well but the problem remained as it is.Ps:- Key HiddenSecurity purposes

:)

 

Printer isn´t working after latest update.

After the latest update from Windows, my Canon Pixma ip6600 printer isnt working. In Device Manager it shows up as working properly but when I go to print it isn´t listed as an option in any programs. Troubleshoot suggests it´s a USB 2 printer on a USB
3 port and that that´s the problem but that cant be since it worked fine before the update. I´ve tried to uninstall and plug it back in but that doesn´t work either.

 

Cortana isn´t working

When I hit enter, it did something, but there´s still no Cortana, even after restart. So I tried it again, but now it says that it failed, because it´s already installed and it´s working in PC. So it should work, but Cortana still isn´t here.

 

Graphics Card not detected anymore

From one day to another, my graphics card (Radeon HD 6870) was not detected anymore.

The card is not listed in the device manager anymore.

So far I tried: take the card out and put back in, to see if any contacts didn´t work, installing the latest AMD driver manually and I tried reseting my BIOS, but I´m not sure if I did it correctly.

t still isn´t working.