[Kazun]

Проверил только на O2010:

Код:

$key = "HKCU:\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\Outlook"
$property = "001f3001"
$account = "test@contoso.com"

$acc = Get-ChildItem $key  | Where {$_.property -eq $property} | 
	Get-ItemProperty -Name $property | Select PSPath,@{n="Account";e={(-join [char[]]$_."$Property") -replace "\0"}}
	
$acc | Where {$_.Account -match $account} | Remove-Item -Force -Recurse -WhatIf