Okay... understand that I write these things about six months before you read them

so I had to go dig up the back issue. Unfortunately I'm looking at the online version which doesn't have a page 33 or a middle column... so if I'm answering the wrong question, please accept my apologies.
The screen shot you noticed is because I use a kind of complex setup of virtual machines where each VM "sees" the same physical drives (think of them as clones).
So start with something like this:
"localhost","xp","server2" | % { gwmi win32_logicaldisk -computer $_ }
Substituting appropriate server names, just 3-4 of them as a test. Is that getting you results from different computers?
(BTW - please be patient with me if I'm slow in responding; I'm off to IT Forum in Spain and am going to be eight or nine hours off - thanks)