Navidad is a virus
Sorry for any redundancy. See for example, <http://www.sarc.com/>.
>From that web site:
Discovered on: November 3, 2000
Last Updated on: November 11, 2000 0 9:38:15 PM PST
W32.Navidad is a mass mailing worm program. The worm replies
using MAPI to all Inbox messages that contain a single
attachment. This works with Microsoft Outlook. The worm utilizes
the existing email subject line and body and attaches itself as
NAVIDAD.EXE. Due to the bugs in the code, after being
executed, the worm causes your system to be unusable.