If you have a backup of your config, reset the switch to factory defaults and reload the configuration. If you do not have a backup you will need to reconfigure the switch as it does not have a serial port for password recovery like the Sx300.
Since you lost access to the switch immediately, it is likely that you did not copy the running configuration to the startup configuration. If that is the case, simply rebooting the switch should load the old startup configuration and the old password should work. Any chance there is someone at the same location that could unplug the power for you and then plug it back in?
Introduction:Topology Diagram:Configuration Overview:Related
Information: Introduction: This document describes how to connect SG300
with Catalyst switch via STP. Spanning Tree Protocol (STP) is a Layer 2
protocol that runs on mainly on switches. The spec...
The Sx500 Series Stackable Switches offers different port features. You
can add security to a port, make the port more energy efficient, map a
VLAN to a port, make a port available or not to a specific network
portion, and so forth. The next set of articl...
Recently, HP Networking published a blog post attempting to counter the
favorable third party Miercom report on our Cisco® 200 and 300 Series
Smart and Managed switches: