Parted and a removable HDD (USB)

Hi , I am trying to return a WD Elements HDD to a contiguous state, it had a Fat32 and an EXT2 partition, having deleted the 2 partitions to start again Here is what I have in parted: Model: WD 1600BEV External (scsi) Disk /dev/sdb: 160GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: This disk should be around 850Gb How do I overcome this difficulty, please? Andrew Greig