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\.
To view the log of a different computer, right-click Event Viewer, click Connect to another computer, and complete the Select Computer dialog box. Optionally, to display only SQL Server events, on the View menu click Filter, and in the Event source list, select MSSQLSERVER.o view the Windows application log. On the Start menu, point to All Programs, point to Administrative Tools, and then click Event Viewer. In Event Viewer, click Application.