MyBook Studio II 4TB will not mount and disconnects

I purchased a 4TB Studio II. I have two LaCie 1TB drives holding video, and I thought the Studio II would make a good primary drive, relegating the LaCie drives to backup status. I installed the WD software on my MacBook Pro (2006, 2.16 ghz Intel Core Duo). Everything seemed to work fine. Next I copied 2 TB of video files to the Studio II, which took the better part of 24 hours. I dismounted the drives and everything seemed to work fine.

The next time I powered up the Studio II, it would not mount on the desktop. I tried reinstalling the WD software, andt then the drive mounted. Unfortunately, on my next time to use the Studio II, it would not mount, even after I reinstalled the WD software again. I notice that the logo of the WD software no longer appears in the menu bar, even after reinstalling.

Now the Studio II won’t mount at all. Disk Utilities does not see it.

Does anyone have any suggestions for what to do at this point?