A fun and free Really Small App showing Running Tasks, Current Startups, and CPU & Memory utilization graphs.
A Really Small App also tells you if remote computers are connected to your PC. If you are part of a network and you share printers and files on your PC, then that figure may justifiably be higher than zero. Same story if other computers have been configured to connect to your PC via PCAnywhere, WinVNC, Remote Desktop, or similar. In most other cases, however, a figure higher than zero is something you need to be worried about as it is highly likely to indicate the presence of Trojan viruses, spyware, or adware. If that happens then you should consider using 'The Ultimate Troubleshooter' to hunt them down.
Can be minimized to the System Tray where it also enables you to change your default printer directly from the System Tray. Finally, hovering the mouse over the System Tray icon for the app gives you an abbreviated summary of the stats it is tracking for you, or you can have an unobtrusive monitoring window showing at all times.