Alert when someone connects to my PC

I'm sharing various folders on my Windows 7 PC. When I go to the Computer Management section, I can see if there are any open sessions in my shared folder. When I connect to the PC from another computer, the Sessions section displays information about the connecting computer, such as its IP address. Is there a way that I can get an alert pop up on my Windows 7 PC whenever a new session is opened? So, instead of me having to manually check if someone has connected to my network, I get a popup appearing stating that a new session has started with a certain computer. It would be preferable if this was possible without downloading any tools.

If you're looking for a tool to alert you when someone is accessing your shared folders, see this article:
Monitor and Notify when Shared Folders being Accessed (NetShareMonitor).

For a tool that can tell what file the user is actually accessing and can log it down for future reference:
Track Who Modified or Deleted Files in Your Shared Folder (System Tray Share Monitor).