The Windows Performance Monitor is a performance monitoring tool, which come along with the windows operating system. The Performance Monitor tool provides various performance counters and factors which can be used to analyze and determine the performance of a system on a whole or that of a specific process over a specific period of me.
Start -> Control Panel -> Administrative Tools -> Performance Monitor
The default counter provides a fair idea of the system in all parameters like CPU, Memory, Disk I/O etc, this counter starts running once you open the Performance Monitor tool, this is the very basis counter which needs no configuration. We can also create our own performance counters and measure the system performance in specific areas, by configuring the counters appropriately.
The below screen shows the output of the default counter, which starts running once the Performance Counter is started.