I've just tried deleting the snapshots from this virtual machine running ESXI5, so that I can grow the Thick Partition. I've now got the below error message when I try to start the VM, the VM also can't be grown above 0 MB i assume for the same reason as below. I've checked the datastore and the original VMDK is still there.

Reason: The system cannot find the file specified.
Cannot open the disk 'VM1-PG-000002.vmdk' or one of the snapshot disks it depends on. 
VMware ESX cannot find the virtual disk "VM1-PG-000002.vmdk". Verify the path is valid and try again. 

How do i tell ESXI5 to use the proper VMDK?