Today one of my minis (model 3,1 and over 3 years old) used as an entertainment center locked up, won't boot and won't respond when I examine it with Disk Utility. Drive replacement time! Luckily I wanted a mini for upgrading to see how well I can do a repair on it myself. Found out that a putty knife in my garage will make quick work of taking the cover off, so I ordered the following from OWC: 1. 120GB SSD hard drive (I don't need much capacity, so why not?). 2. 4GB of RAM to upgrade the 2GB in the box. Yes, it actually has been running fine with 2GB. And I'll upgrade from Snow Leopard to Mountain Lion while I'm at it. That's why I'm adding RAM. My goal this summer is to get all my minis upgraded to Mountain Lion, with my Snow Leopard Server system going to Server.app. All three systems will get a dose of RAM. By the end of the year all but the server will be on Mavericks.