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\.
In the Computer Management console, connect to the computer whose event logs you want to view or manage. Expand the System Tools node by clicking the plus sign (+) next to it and then double-click Event Viewer. You should now see a list of logs, as shown in Figure 3-8. Select the log you want to view.