Security Basics: Initial Machine login - Computer Forensics 101

["Michael Condon" <mjc001 () juno com>]

Here is a Computer Forensics 101 question.
Suppose a distraught woman comes to me with her husband's laptop and wants 
me to
search it for information about a suspected marital indescretion.
1. Assuming it is an XP/Vista machine, how can I log in as administrator?
2. Is the second approach to make a bistream copy of the hard drive using an 
external USB har drive enclosure and proceed that way?