Found this problem afta a vista reinstal windows mail had vanished, the link was in my programs menu but the link led to nowhere. found this simple fix.

When you open Default Programs applet, and click Set your default programs link, Windows Mail may be missing from the list of programs.

To reinstate Windows Mail entry to the default programs listing, follow these steps:

* Download mailclients.reg from the Attachments section below, and save to Desktop
* Right-click mailclients.reg and choose Merge
* If you are prompted for an administrator password or confirmation, type the password or provide confirmation
* Click Yes to continue.

http://www.winhelponline.com/downloadattachment.php?aId=15d07b24bfb57425f1e72018886ed035&articleId=220

problem sorted