Datastore Folders are empty

Hi,

I recently had to do a reinstall of ESXI 5 due to a server fault on a Dell R320.  I chose the option to install the software (rather than upgrade it) but to preserve the datastore.  The server now boots into ESXI 5 again but when I browse the datastore from the vmware client, although the folders are there, they all appear to be empty.  The drive is reading as though it is nearly half full so I can't understand why none of the virtual machine hard disks or images are showing up.

Any help would be greatly appreciated.

Thanks