Does the system boot using UEFI? That will cause such problems.
Use of the phrase "old XP machine" makes me doubt this could be the problem but you never know.....
Try booting using the USB again & check what partitions you have on the hard drive:
Accessories > Disks
Click on your hard drive and does it show "Master Boot Record" or "UEFI" next to Partitioning?
Do you see partition types other than NTFS?