With Windows Taskmanager you can see which applications, processes and services are running on your computer. Also you can see how busy the processor(s) of your computer are and how much internal memory is being used.

Taskmanager gives a deeper insight into your computer. For example, you can see which process consumes the most cpu (central processor unit) time or internal memory.

You can launch Taskmanager by pressing the 'Ctrl' 'Shift' 'Esc' keys at the same time, or by right clicking on your taskbar and selecting Taskmanager.

In case you're already familiar with Taskmanager, I recommend taking a closer look at a tool called 'Process Explorer'. Process Explorer gives even more insight into your computer internals. Process Explorer can be downloaded for free from the 'Process Utilities' section of Microsoft Sysinternals site:

http://technet.microsoft.com/en-us/sysinternals/default.aspx

With Process Explorer you can see for example a hierarchy of processes (see which process is owned by another process). You can also easily see which processes are launched or stopped. You can pause the display of processes. The name of the company of the process can be displayed, however that's no guarantee this company also made the process. For that reason you can verify all processes with certificates.

You can also see which process causes a 'spike' in the used 'cpu' time. The tool is worth investigating further. It can also help track viruses and spyware.

Microsoft offers webcasts about this tool on the following site:

http://www.microsoft.com/emea/spotlight/

A must see are all webcasts by Mark Russinovich. In order to watch the webcasts, you have to install Microsoft Silverlight, which can be obtained from the following site:

http://www.microsoft.com/silverlight/default.aspx