HDD off-line status won't change

I have a 1.5Tb USB-interface HDD that's decided to misbehave, and I will have to recover it and its contents.

Plugging the device into windows 7 gets the new device tone, but it's not recognised in explorer. The control panel/device manager/disk drives sees it, identifies the item and says its working OK.

Opening DD11 and the management console presents the image of attached disks - see attached image. Disk 5 is the one this topic applies to. It says, "off-line, uninitialised". Clicking the operations item in the LH paneL gets an action window to change the status to on-line so that operations (like, re-format etc can be done) and message that the option will be executed when OK is clicked. Click OK and the pendulum icon turns for a few seconds and then the whole panel disappears. And after that, there's no change: the console display still says "offline, uninitialised" even after a refresh of the display. A DD11 restart makes no difference to this result.

Some clarification of the DD11 result would be appreciated.

Davidk