Ultra II not showing in Dashboard

I have a 480GB Ultra II which we had planned ot use as an upgrade to my 240GB SSD. however, in the migration process something has caused the 480GB to now become a ghost disk in Sandisk Dashboard and Windows cannot intialise the disk. I have looked at it through Partition Wizard Pro and it shows read only and a bad disk. is this now just a dead drive or can it be resurrected? any help please

you can try the diskpart clean command. If that will not clear all the partitions the drive is likely bad and will need to be replaced. 

Thanks for the reply. do you have the syntax for the command?