I have a home network with 2 XP machines and 1 Vista machine. Several months ago, my HP PSC 2355 all-in-one printer started failing. This printer was physically attached to one of the XP machines and all could share just by adding the printer to the other 2 machines. Then I bought a new HP Photosmart C5550 all-in-one printer and attached it to the same XP machine. I could then add the other XP machine but was unable to add the printer to the Vista machine. The Vista machine would not share. The workgroup is the same on all 3 machines. I could physically attach the printer to the Vista machine, load the software and it would print. But the 2 XP machines would not share. After talking to the HP support they told me that the newer printers would not share between XP and Vista. The alternative was a print server. I found a cheaper alternate solution. I bought a $12 2 channel USB switch. I attached one XP machine and the Vista machine to the switch and the printer to the switch. The switch has 2 buttons. I just select which machine I want tp print from with the buttons , loaded the software or drivers on the Vista machine also and viola !!! I can print from all machines. Hope this helps anybody with the same problem.