GPG4Win is an openPGP compliant windows engine that allows you to easily make your own public keys and decrypt in Outlook.
First create a new certificate, then send it as an attachment in a text only email to <email@example.com> to see if you recieve a reply.
To create a revocation certificate (command line only):
gpg --output "C:\some\path\myrevocation.asc" --gen-revoke [your key-ID]
NB if you're testing the revocation certificate by importing it, make sure you have a backup of the secret key as well as the public key. Restoring only the public key means your certificate remains revoked! Also, test this if you must BEFORE you have uploaded your public key to a public key server.
If you get the content as a text block (eg via Gmail) you can use VisualGPG to decode it:
You need an Outlook plugin, as the GPG4Win plugin only supports Outlook 2003 / 2007.
This page describes how to integrate a free but limited plugin.