I'm having trouble with disks on my machine. I'm unable to boot and currently trying to clean install Ubuntu. When I use Gparted with bootable usb disk, I can remove all partitions on my disk and when I hit apply button it says job is done but as soon as the success message disappears, it shows all the old partitions as they were before.
Update: when I use Disk utility, after hitting -
button to delete any partition, nothing happens.