How can get title of inactive winodws

The problem with enumerating processes is that you don't get windows that way; more specifically, you don't get window handles that way. To get the window handle of the top-level window of a process you need to enumerate all top-level windows looking for the process's process id. So instead of enumerating processes as you are suggesting, it is better to enumerate top-level windows and look for the class name instead of enumerating processes looking for the executable's name. See Tutorial: Capturing and Running IE Instances in a Windows control; it describes enumerating top-level windows to find IE windows. You can do the same for Chrome except use Chrome_WidgetWin_0 for the class name instead of IEFrame.

Use Spy++ to determine a window's class name and other properties of the window.

Then see Working with Win32 API in .NET. Use EnumChildWindows to find the tabs.