In my task manager I find 2 Explorer instances running. Is it suspicious? I was always under the impression Explorer will have only one instance running.
OS: Windows 7
Explorer.exe has two different uses. Its primary purpose is to provide the ability to interface with the file system at all (giving you a desktop and start menu, for instance). It also, though, is used to browse the file system. You can select an option to launch folder windows in a separate process in the Folder Options control panel. It is deselected by default. If it is disabled, the main explorer.exe process is used for this task. It may be turned on though, to improve system stability.