PowerShell function that will find a Windows Installer component in the registry and will delete the component.

gistfile1.ps1

# This function will accept component GUIDs from the pipeline
# and will attempt to find and delete the component records
# in the Windows Installer registry hive if they exist.
#
# For whatever reason, Windows Installer reverses the GUIDs
# when creating the component records in the registry. This
# function implements the logic for reversing the GUID values
# and building the correct registry key for each component.
function Remove-WindowsInstallerComponent {
    $flags = [System.Text.RegularExpressions.RegexOptions]::Compiled -bor [System.Text.RegularExpressions.RegexOptions]::Singleline
    $regex = new-object System.Text.RegularExpressions.Regex "\{?(?<a>[0-9A-F]{8})-(?<b>[0-9A-F]{4})-(?<c>[0-9A-F]{4})-(?<d>[0-9A-F]{4})-(?<e>[0-9A-F]{12})\}?",$flags

    foreach ($componentId in $input) {
        write-host "$componentId"
        $match = $regex.Match($componentId)
        if ($match.Success) {
            $a = $match.Groups["a"].Value.ToCharArray()
            $b = $match.Groups["b"].Value.ToCharArray()
            $c = $match.Groups["c"].Value.ToCharArray()
            $d = $match.Groups["d"].Value.ToCharArray()
            [char[]]$d1 = $d[0..1]
            [char[]]$d2 = $d[2..3]
            $e = $match.Groups["e"].Value.ToCharArray()
            [char[]]$e1 = $e[0..1]
            [char[]]$e2 = $e[2..3]
            [char[]]$e3 = $e[4..5]
            [char[]]$e4 = $e[6..7]
            [char[]]$e5 = $e[8..9]
            [char[]]$e6 = $e[10..11]

            [System.Array]::Reverse($a)
            [System.Array]::Reverse($b)
            [System.Array]::Reverse($c)
            [System.Array]::Reverse($d1)
            [System.Array]::Reverse($d2)
            [System.Array]::Reverse($e1)
            [System.Array]::Reverse($e2)
            [System.Array]::Reverse($e3)
            [System.Array]::Reverse($e4)
            [System.Array]::Reverse($e5)
            [System.Array]::Reverse($e6)

            $d = [System.String]::Format("{0}{1}", (new-object System.String @(,$d1)), (new-object System.String @(,$d2)))
            $e = [System.String]::Format("{0}{1}{2}{3}{4}{5}", (new-object System.String @(,$e1)), (new-object System.String @(,$e2)), (new-object System.String @(,$e3)), (new-object System.String @(,$e4)), (new-object System.String @(,$e5)), (new-object System.String @(,$e6)))

            $a = new-object System.String @(,$a)
            $b = new-object System.String @(,$b)
            $c = new-object System.String @(,$c)
            $d = new-object System.String @(,$d)
            $e = new-object System.String @(,$e)

            $key = "hklm:\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Components\$a$b$c$d$e"
            if (test-path $key) {
                remove-item $key -Recurse -ErrorAction Continue
            }
        }
    }
}