Your friend was scammed by crimminals. Microsoft never phones and there is no Microsoft software to download for remote connection. Did he give them any banking or credit card information? Is so he should call the bank or credit card people right away and put a stop on the transaction. People often wont admit this at first because they are so embarrased that they could be so gullible and so ask gentlly as a friend.
If you are able to boot the Windows install USB then
Boot from the media and choose “Repair your computer” (down on lower left of the “Install Now” screen).
choose troubleshoot[br]
choose advanced option[br]
choose command prompt [br]
type '''diskpart''' and press enter[br]
type '''list disk''' and press enter[br]
this shows all drives available, DVD/USB and hdd, make note of hdd number[br]
type '''Select disk X - where X is the number of the hdd you want to wipe, change X to that number''' and press enter[br]
once the drive you want to wipe is chosen, type '''Clean All'''[br]
exit and close.
That should do it.
''The "'''clean all'''" command fills every sector on the disk with zeroes, so information can't be recovered. It completely deletes all data stored on the disk, all its partitions, folders, files etc - everything. The operation usually takes a lot of time, so be careful and patient.''
You could also just take the drive out and connect to an external USB to SATA adapter cable and wipe the drive from another computer.
Have you updated the BIOS? The UEFI should have ASUS EZ Flash built in.
Let us know how it goes.