I got a dell optiplex off ebay. I was installing windows 10 on it after formatting the drive. I reached the point where it asks you for a serial key or you can say you do not have one.

 

Instead I get a welcome to invesco. Where I have to put in a invesco email or a key from a usb device.

 

Clearly this computer was a corperate system. I would like to know how to wipe what ever the security is on it and restore it to factory defaults.

Thank you