As a consequence of the deficiency in CD40 ligand, the T-lymphocytes in patients with X-linked Hyper IgM (XHIGM) are unable to instruct B-lymphocytes to switch their production of immunoglobulins from IgM to IgG, IgA and IgE.
Windows event logs are also files, but they are commonly locked by Windows (Event Log Service) and it is impossible to open these files on live system. But if the computer is started from another disk or the system drive from the analyzed machine is connected to another computer, you can read event logs as files. The default location of event logs on Vista/2008 and better is C:\Windows\System32\winevt\Logs\.
Techopedia explains Event Log. An event log is a basic log book that is analyzed and monitored for higher level network intelligence.. It can capture many different types of information. For example, it can capture all logon sessions to a network, along with account lockouts, failed password attempts, etc. It can also record different types of application events, such as application errors, closures or other related events. An event log is often used by a tool called security information and event management tool. This tool provides a higher level of analysis of the contents of an event log to help network administrators determine what is going on within a network.