A nice set of software tools provided by Nir Sofer can help you to view or recover your user ids and passwords stored in Internet Explorer, Outlook, Thunderbird, Instant Messengers like MSN, Gtalk, Yahoo! (5.x and 6.x versions only) etc. You can also extract user info like product key and Id of Windows, MS Office, Exchange Server and SQL Server installed in your PC.
Mail PassView: The tool needed to view or recover Email client software (Outlook, Thunderbird etc) stored ids and passwords.
To view/recover ids and passwords stored in a IM client (Gtalk, Yahoo!, MSN etc) you can use MessenPass.
To view/recover product keys and Ids you can use ProduKey.
To view/recover Internet Explorer Stored id and passwords you need IE PassView.
You can download these and lots of other id password recovery tools like these from www.nirsoft.net.
*Note: These tools don't contain any trojan/virus and these are not hack tools which can send recovered ids and passwords over Internet. Some anti-virus programs may detect these tools as virus or hack tools, you can ignore these warnings.