Grazie per i vostri suggerimenti, ma ho risolto il problema e inserisco il codice che ho utilizzato.
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Imports System
Imports System.Diagnostics

Class MyEventlogClass

Public Shared Sub Main()
Dim myEventType As String = Nothing

Dim ora As String
Dim min As String

Dim myEventLog As New EventLog("System", ".")
Console.WriteLine("1:Information")

Console.WriteLine("Select the Event Type")
Dim myOption As Integer = Convert.ToInt32(Console.ReadLine())

Select Case myOption
Case 1
myEventType = "Information"
Case Else
End Select

Dim myLogEntryCollection As EventLogEntryCollection = myEventLog.Entries
Dim myCount As Integer = myLogEntryCollection.Count

Dim i As Integer
For i = myCount - 1 To -1 Step -1
Dim myLogEntry As EventLogEntry = myLogEntryCollection(i)

Dim str As Long
Dim dent As String
str = myLogEntry.InstanceId


If str = 2147489653 Then

dent = myLogEntry.TimeWritten.Date

If Dataorario = dent Then

ora = myLogEntry.TimeWritten.Hour()

If Len(ora) = 1 Then
ora = "0" & ora
End If

min = myLogEntry.TimeWritten.Minute
If Len(min) = 1 Then
min = "0" & min
End If


horario = ora & ":" & min
Exit Sub
End If

End If
Next i

End Sub
End Class


Ciao a tutti