The Event Viewer tool maintains three log files containing the System, Application, and Security event messages. However, the Event Viewer tool may not be able to write event messages to one of these log files if there is no disk space available. To increase the disk space that can be used for these log files, you can modify their default location.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
To modify the location of the Event Viewer log files:

1.	Click Start, click Run, type regedt32, and then click OK.
2.	On the Windows menu, click HKEY_LOCAL_ MACHINE on Local Machine. • For the System log: a. Click the System\CurrentControlSet\Services\EventLog\System folder, and then double-click the FILE value. b. Type the new drive and path in the String box, include the file name \SysEvent.Evt, and then click OK. The default path is %SystemRoot%\System32\Config\SysEvent.Evt • For the Application log: a. Click the System\CurrentControlSet\Services\EventLog\Application folder, and then double-click the FILE value. b. Type the new drive and path in the String box, include the file name \AppEvent.Evt, and then click OK. The default path is %SystemRoot%\System32\Config\AppEvent.Evt • For the Security log: a. Click the System\CurrentControlSet\Services\EventLog\Security folder, and then double-click the FILE value. b. Type the new drive and path in the String box, include the file name \SecEvent.Evt, and then click OK. The default path is %SystemRoot%\System32\Config\SecEvent.Evt
3.	Quit Registry Editor, and then restart the computer.