Poser is extremely forgiving of moving runtimes and folders.

 Go into windows explorer or whatever your basic file management system and navigate to Poser 7/runtime/libraries/pose

Within Pose make separate folders for at least Mats, Inj and regular Poses.  Mine is broken up into many different catagories.  For instance, I have separate folders for Aiko Mats and Clothing MAT and special effects and so on.

Move the Mat file AND it's associated PNG file into the new Mat folder.  It should look like
Runtime/Libraries/Pose/Mat/ and then whatever Mat files you have.

Repeat until you are organized.  It may take a bit depending on your content.  But it's well worth it.  I have 25GIG but I have heard of runtimes of 250 Gigs.  Without proper organization your workflow just slows you down.

By the way, something I can't afford right now ($64 american) is the PZDB databate program sold here.  I am using the 30 day FREE  trial and it makes working with so much content fast and fun!  Try it out.  When I can save up my bucks, I'm snatching it up at the next big sale.

Good Luck!

Repeat with all