New
#11
Both Homegroups and Workgroups won't work on cross Op systems, those are made for your Windows 7 machines only.
For machines running something other than Windows 7 use the public file sharing option, set everything as shown below on the shared Windows 7 machine. You will also need to enable sharing with full access rights on the Vista and XP machines.
You can use the Public password protected option "on or off" to toggle if a machine can be accessed or not.