User registry through PS

 New-PSDrive HKU Registry HKEY_USERS | Out-Null

$user = Get-WmiObject -Class Win32_ComputerSystem | Select-Object -ExpandProperty Username

$sid = (New-Object System.Security.Principal.NTAccount($user)).Translate([System.Security.Principal.SecurityIdentifier]).Value

$key = "HKU:\$sid\Software\Test"

$reg = Get-Item -Path $key -ErrorAction SilentlyContinue

if (-not $reg) {

    Write-Host "Registry key didn't exist, creating it now"

    New-Item -Path "HKU:\$sid\Software" -Name "Test" -Force | Out-Null

}

if (-not $reg) {

    Write-Host "Registry key didn't exist, creating it now"

    New-ItemProperty -Path "HKU:\$sid\Software\Test" -Name "Testing" -Value "working" -PropertyType String | Out-Null

} else {

    Write-Host "Registry key changed to 1"

    Set-ItemProperty -Path "HKU:\$sid\Software\Test" -Name "Testing" -Value "working" | Out-Null

}