#here's a typical way to use WMI in PowerShell
$os=get-wmiobject Win32_OperatingSystem

#list properties and values 
#Selected.System.Management.PropertyData
#works fine for a single instance
$os.properties | select name,value

#although you could do this
$d=Get-WmiObject win32_logicaldisk -filter "drivetype=3"
$d | foreach {$_.properties | select name,value }

#save properties as an array of string names
[string[]]$prop=$os.properties | Select -expand name
#select all of them
$os | Select -Property $prop

#or as a one liner
$os | Select -property ([string[]]($os.properties | Select -expand name))

#or as a more complex one liner
Get-WmiObject win32_OperatingSystem | foreach {Select -InputObject $_ -Property ([string[]](Select -InputObject $_ -expand Properties | Select -expand Name))}

#an alternative using [WMIClass]
[wmiclass]"win32_operatingsystem" | Select -expand Properties | Select name

#which leads to this
([wmiclass]"win32_operatingsystem").Properties

#...to this
([wmiclass]"win32_operatingsystem").Properties | Select -expand Name

#we can use the same technique with a slightly easier one-liner
get-wmiobject win32_operatingsystem | 
select -property ([string[]](([wmiclass]"Win32_Operatingsystem").properties | select -expand name))

#how about a shortcut?
$p={[string[]](([wmiclass]"Win32_Operatingsystem").properties | select -expand name)  }

get-wmiobject win32_operatingsystem | select -property (&$p)

#now let's make it flexible
$p={Param([string]$class) [string[]](([wmiclass]$class).properties | select -expand name)  }

#test it
&$p win32_bios

#use it
get-wmiobject win32_bios | select -property (&$p "win32_bios")