So basically you can't perform any
steps that are requested. I've never seen that.
Try resetting BIOS to defaults using another method given here: How To Clear CMOS (Reset BIOS)
Can you boot into the installer to get to the drive selection screen, select Drive Options link, delete all partitions, then Click Next to have installer create and format install partition and begin install?
If you can do that then you should be able to run the Diskpart commands. I've never heard of it showing Diskpart in Command line but not allowing the commands to be typed. It would almost have to be a corrupt installer, but then it wouldn't get to Diskpart if it is.
Do you have anyone there who can help you follow the steps that have been given from the top? At least one of these steps should work. As it stands there are many steps which have backed up - including the hardware tests which were ignored. To successfully troubleshoot you have to be utterly thorough without missing a single step, reporting back in detail.