Overriding windows system setup password

My family's computer is down, and last night, I was trying to boot up an old computer that my family had several years ago when I was in middle school. We had an extra copy of Windows XP that I was going to try to install onto this old computer, but when I was in middle school, I got grounded and my mother created a system password. It isn't a regular username/password; it's one that comes up before anything else comes up--you can't go into setup without knowing it. My mother passed away a few years ago, so I can't ask her about it, and I'm wondering if there is anyway to override it. None of my friends have ever even heard of such a password. I'm not sure what version of Windows the computer ran on, but I think it was pre-XP. If anyone could help me, I would appreciate it. My e-mail address is arjones7@usieagles.org . Thanks.

I'm honestly not sure what it was. All I know is that the computer starts, displays the COMPAQ screen for a few seconds, then goes directly to a black screen with a blue box in the center that wants a password.

But assuming it is a hard drive password, how would I enter the bios?