The originating IP is the location information that gets added to the message when one uses Hotmail. By using tracing programs (such as utrace.de) one can try to determine the location where the message was written. it should match where you believe the person is at a given moment in time. Often it will seem that the message has originated in Nigeria. If your contact was not there, then we can safely conclude the message is fake.
Such messages are common, and can be due to a result of a variety of reasons. The most common is that the email address is harvested (ie. collected) from online public sources (such as mailing lists, blogs, websites, etc) and then used by spammers. One recommendation is to suggest to key contacts that they use two email addresses - one for public messages, and another for private/confidential messages. The private email would be used rarely, and not placed publically. Thus depending what email is used to contact you can tell if the message is real or not.
Another approach, is to ask the contact to include a previously agreed to phrase in "help" messages. That phrase, in a way is used to authenticate the source. If it is absent, well, you know the message is either fake or being sent by a third party.
refs - online tools used to analyze headers: