Это будет перевод VB.NET этого ответа C # на аналогичный вопрос :
Dim allDrives As DriveInfo() = DriveInfo.GetDrives()
For Each d As DriveInfo In allDrives
If d.IsReady AndAlso (d.DriveType = DriveType.Removable) Then
Dim startInfo As New ProcessStartInfo()
startInfo.FileName = "format.com"
startInfo.Arguments = "/fs:FAT /v:MyVolume /q " & d.Name.Remove(2)
startInfo.UseShellExecute = False
startInfo.CreateNoWindow = True
startInfo.RedirectStandardOutput = True
startInfo.RedirectStandardInput = True
Dim p As Process = Process.Start(startInfo)
Dim processInputStream As StreamWriter = p.StandardInput
processInputStream.Write(vbCr & vbLf)
p.WaitForExit()
End If
Next