When I look at the Win32_ComputerSystem class, it shows loads of properties like Status, PowerManagementCapabilities, etc. However, when in PowerSh
I like
Get-WmiObject Win32_computersystem | format-custom *
That seems to expand everything.
There's also a show-object command in the PowerShellCookbook module that does it in a GUI. Jeffrey Snover, the PowerShell creator, uses it in his unplugged videos (recommended).
Although most often I use
Get-WmiObject Win32_computersystem | fl *
It avoids the .format.ps1xml file that defines a table or list view for the object type, if there are any. The format file may even define column headers that don't match any property names.