OS x Mavericks network install - "this disk is locked"

[StressedOutUser]

When trying to Install OS X Mavericks from network install, after the download I get to a screen which displays

"Select the disk where you want to install OS X"

I can only see one drive, when I select this, It says "this disk is locked"
Because of this the install icon is greyed out.

What Can I do to either delete this disk that shows, or create another?

 

[Meister]

Call care (you can pay for a one off ticket), they will likely tell you to go the store.

 

[maflynn]

Did you try to run Disk Utility to repartition the drive and then do the install?

 

[StressedOutUser]

Did you try to run Disk Utility to repartition the drive and then do the install?

How can I get into disk utility?

My partitions are all messed up.

When holding cmd + r on bootup, once my macbook has finished fetching the files, it goes to the page of selecting a disk where to install, I dont see any more options here for disk utility