Welcome to the community, Woody722!
I'm very sorry to hear about your WD external drives not being detected!
You might have encountered a
Signature Collision, if you've tried plugging more than one WD external in the system simultaneously. Here's a link from our KB that explains this issue and how to solve it:
http://products.wdc.com/support/kb.ashx?id=yaXNJf
If that doesn't help, since they are all the same model, I'd suggest to try swapping the USB cables between the drives and see if that will make them appear. Another thing you should try is connecting them to a different computer. I'd also suggest you to check Disk Management in Windows, while plugged to your computer and check if they are present there as Disks.
I'd also strongly recommend backing up any data from them once you can access them and testing the drives using WD's Data LifeGuard diagnostics. It will help us determine what is the health and SMART status of the HDDs, just make sure you run both the QUICK and the EXTENDED tests from the utility. Here's a link to it:
http://products.wdc.com/support/kb.ashx?id=rAFpGN
Keep me posted with the results! Hope this helps!
SuperSoph_WD