Hi Guys, Very new to anything Apple as my background is totally in PCs but a customer has asked me to look at his PowerBook G4 and wants to upgrade the O.S. as his new printer is not supported (he called Apple and they told him to upgrade the OS).. System Info as follows: Machine Name: PowerBook G4 15" Machine Model: PowerBook5,4 CPU Type: PowerPC G4 (1.1) Number Of CPUs: 1 CPU Speed: 1.33 GHz L2 Cache (per CPU): 512 KB Memory: 1.25 GB Bus Speed: 167 MHz Boot ROM Version: 4.8.4f1 15GB if free hard drive space currently but will be freeing up an additional 10-15 once I archive his images. Current O.S. 10.4.11 What are my options for upgrade? Could I take it all the way up to Mountain Lion?