need some help with Apple computer....

[SanPancho]

bought a used imac from friend of friend, who was leaving for round the world trip. he wiped it clean before he left.

unfortunately i am now trying to reinstall sierra and it keeps telling me the disk is locked, so i cant reinstall.

i was told to go into disk utility and unlock the disk, but that isnt an option. my only options are first aid and partition.

no idea what to do here.

thanks

 

[Horseflesh]

At this point I would try deleting the existing partition and re-creating it. Use MacOs Journaled. Do not choose the case sensitive partition scheme.