Try to locate a white label on the mainboard, which has a serial number and a part number in ABCDEF-123 format. Those will help to identify the server.
There is no way to reset the password for the server management console. Typically when I install the management console, I would use the same Windows password. Have it a try, it may work.
Also, you can use a system event log utility to check for the actual error on your server. As I do not know which server you are using, there are different versions depending on the platform.