Old MacBook Pro OS reinstall help? I started by erasing my disk. Then at the startup I got the question mark, so I restarted in recovery mode and opened the disk utility. Now almost all everything is greyed out and there is little I can do on the disk. Is there still a way to fix this?

Old MacBook Pro OS reinstall help? I started by erasing my disk. Then at the startup I got the question mark, so I restarted in recovery mode and opened the disk utility. Now almost all everything is greyed out and there is little I can do on the disk. Is there still a way to fix this?