Windows identifies which application to open a file with by examining which of the following?

After suspecting a change in MS-Exchange Server storage archive, the investigator has analyzed it. Which of the following components is not an actual part of the archive?

Heather, a computer forensics investigator, is assisting a group of investigators working on a large computer fraud case involving over 20 people. These 20 people, working in different offices, allegedly siphoned off money from many different client accounts. Heather responsibility is to find out how the accused people communicated between each other. She has searched their email and their computers and has not found any useful evidence. Heather then finds some possibly useful evidence under the desk of one of the accused.
In an envelope she finds a piece of plastic with numerous holes cut out of it. Heather then finds the same exact piece of plastic with holes at many of the other accused peoples desks. Heather believes that the 20 people involved in the case were using a cipher to send secret messages in between each other. What type of cipher was used by the accused in this case?

The following is a log file screenshot from a default installation of IIS 6.0.

What time standard is used by IIS as seen in the screenshot?

A suspect is accused of violating the acceptable use of computing resources, as he has visited adult websites and downloaded images. The investigator wants to demonstrate that the suspect did indeed visit these sites. However, the suspect has cleared the search history and emptied the cookie cache. Moreover, he has removed any images he might have downloaded. What can the investigator do to prove the violation? Choose the most feasible option.