Its most likely a bios password, but can't be fully sure. I have to ask, is this really your laptop. I have never heard of a laptop magically getting a password after never having one, unless someone is playing a prank on you and put on or if you accidentally put one on your self.
either way if it really is the bios password, there is a way to reset it, and if your afraid to take your laptop apart you might want to get someone to help you. There is either a switch or a cmos battery, or even both in some cases.
There is the other possibility that it is a hard drive password.
most the time laptop vendors like to hide the cmos battery so its not easy to reset the password.
you will have to get the service manual for your laptop on how to take it apart and where the cmos battery or cmos reset switch is. also if the battery is easy to find or switch make sure that your laptop is unplug, and the main battery is not attached either.