gistfile1.ps1

function Get-InstalledSoftware {
	<#
	.SYNOPSIS
		Retrieves a list of all software installed
	.EXAMPLE
		Get-InstalledSoftware
		
		This example retrieves all software installed on the local computer
	.PARAMETER Name
		The software title you'd like to limit the query to.
	.PARAMETER Guid
		The software GUID you'e like to limit the query to
	#>
	[CmdletBinding()]
	param (
		[string]$Name,
		[ValidatePattern('\b[A-F0-9]{8}(?:-[A-F0-9]{4}){3}-[A-F0-9]{12}\b')]
		[string]$Guid
	)
	begin {
		Write-Verbose -Message "$($MyInvocation.MyCommand) - BEGIN"
		$UninstallKeys = "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall","HKLM:\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall"
        New-PSDrive -Name HKU -PSProvider Registry -Root Registry::HKEY_USERS | Out-Null
		$UninstallKeys += Get-ChildItem HKU: | where { $_.Name -match 'S-\d-\d+-(\d+-){1,14}\d+$' }| foreach {"HKU:\$($_.PSChildName)\Software\Microsoft\Windows\CurrentVersion\Uninstall" }
		
	}
    process {
		try {
			if (-not $UninstallKeys) {
				Write-Verbose -Message 'No software registry keys found'
			} else {
				foreach ($UninstallKey in $UninstallKeys) {
					$friendlyNames = @{
						'DisplayName' = 'Name'
						'DisplayVersion' = 'Version'
					}
					Write-Verbose -Message "Checking uninstall key [$($UninstallKey)]"
					if ($PSBoundParameters.ContainsKey('Name')) {
						$WhereBlock = { $_.GetValue('DisplayName') -like "$Name*" }
					} elseif ($PSBoundParameters.ContainsKey('GUID')) {
						$WhereBlock = { $_.PsChildName -eq $Guid }
					} else {
						$WhereBlock = { $_.GetValue('DisplayName') }
					}
					$SwKeys = Get-ChildItem -Path $UninstallKey -ErrorAction SilentlyContinue | Where-Object $WhereBlock
					if (-not $SwKeys) {
						Write-Verbose -Message "No software keys in uninstall key $UninstallKey"
					} else {
						foreach ($SwKey in $SwKeys) {
							$output = @{ }
							foreach ($ValName in $SwKey.GetValueNames()) {
								if ($ValName -ne 'Version') {
									$output.InstallLocation = ''
									if ($ValName -eq 'InstallLocation' -and ($SwKey.GetValue($ValName)) -and (@('C:', 'C:\Windows', 'C:\Windows\System32', 'C:\Windows\SysWOW64') -notcontains $SwKey.GetValue($ValName).TrimEnd('\'))) {
										$output.InstallLocation = $SwKey.GetValue($ValName).TrimEnd('\')	
									} 
									[string]$ValData = $SwKey.GetValue($ValName)
									if ($friendlyNames[$ValName]) {
										$output[$friendlyNames[$ValName]] = $ValData.Trim() ## Some registry values have trailing spaces.
									} else {
										$output[$ValName] = $ValData.Trim() ## Some registry values trailing spaces
									}
								}
							}
							$output.GUID = ''
							if ($SwKey.PSChildName -match '\b[A-F0-9]{8}(?:-[A-F0-9]{4}){3}-[A-F0-9]{12}\b') {
								$output.GUID = $SwKey.PSChildName
							}
							New-Object –TypeName PSObject –Prop $output
						}
					}
				}
			}
			Write-Verbose -Message "$($MyInvocation.MyCommand) - END"
		} catch {
			Write-Error -Message "Error: $($_.Exception.Message) - Line Number: $($_.InvocationInfo.ScriptLineNumber)"
			Write-Verbose -Message "$($MyInvocation.MyCommand) - END"
			$false
		}
	}
}