XPS 9575 Many problems

I found a XPS 9575 in the inventory of where I am working. I needed a laptop. I asked them if I can have it and they said yes. The device is great. It is fast and powerful but I am having many problems. After I reset the device, it didn't accept the activation key. it is still inside the device. Error code is 0XC004F025. Secondly, it doesn't accept the service tag and the express code or whatever it is called. Third problem is My ram usage never goes under %40. Even though I am using around 1GB of ram ( I have 8). 4th and the one that creates the biggest problem I think is that I cant update the bios and the firmware. It restarts and fails. 5th and the weirdest one is it doesn't detect the cpu. It shows that I have a Intel Cpu 0000 insted of i5-8305g. I did all of the updates