How is it 'open on another client'? Is it sitting on the local hard disk?

You would have to set up a share on that disk. I do not know of any other way of direct access to a local hard disk. This can be secured using the standard NT tools, but it would be easier to have it on a shared disk.

Or maybe, you mean an Access db opened exclusively? Get them to open it shared and then connect read-only.

Just some ideas,

Paul.