Google is your friend; simply query it with a question like "how to clear the interface counters on an HP ProCurve (or Cisco or other) switch or router?"
Without you providing the brand and type and model of device, it's challenging to answer your question correctly the first time; you might be asking how to clear the counters on a Windows server or a Sonic Wall firewall.
In the case of Cisco switches, the script that clears all their counters is:
clear count
y
You can also issue the "clear count ?" command and see other options.
