If you check the Don't ask me again (always send information) box when you select an Internet link on the Properties dialog for an event, there is no GUI method to reverse your action.
If you wish to restore the confirmation dialog:
1. Open a CMD.EXE Window.
2. Using REG.EXE, built into Windows XP and Windows Server 2003 and later operating systems, or installed on Windows 2000 from the Support Tools on the Windows 2000 CD-ROM, type the following command and press Enter:
REG ADD "HKCU\Software\Microsoft\Windows NT\CurrentVersion\Event Viewer" /V ConfirmUrl /T REG_DWORD /F /D 1