Format an eSATA hard drive on windows 7

We don't know, what can you do? (drumroll)

Actually, more detail would help. When and how does it tell you that you cannot format it? It may be something as easy as the drive needing to be partitioned first, or much more complicated. Can you post an image of how the drive shows up, if it does show up, in Drive Manager (Control Panel - Administrative Tools - Computer Management - Disk Management tab)?

See if this addresses the issue: , or if it's something more complicated.