If this is a laptop, you may have to buy the software.
Note: If this is a work PC, or a PC that is not yours, or has some sort of RAID array controlled by the motherboard, or has multiple hard drives that boot only in a certain order, you may have to go back into the BIOS and reconfigure it. So make sure you know what some of the settings are before you go and do this:
If this is a desktop PC, and you're talking about your BIOS or boot-up password, you'll need to open the system up and use the reset jumpers on the motherboard to reset your BIOS to it's default settings. Resetting your BIOS will also reset the password. Look near the CMOS battery on your motherboard, there should be a jumper block near it that is sitting on a grid of 3 prongs but is only jumping two of them. Making sure your PC is unplugged, take the jumper off the 2 prongs it's currently sitting on, and move it over to the opposite side of the 3 prongs. Some motherboards have this sort of thing marked as "CMOS Reset" (NOTE: If this is a Dell PC, most of the time they'll have a "CMOS Password Reset" and a "CMOS Reset" set of prongs, if in your case you have a Dell, use the Password Reset.)
It should look something like this:
[__]
|....|....|
[__] is the jumper
move it over like this:
--->[__]
|....|....|
leave it in that position for about (to be safe) 30 seconds. By then it will dissipate the charge from the CMOS battery. Then set it back the the original position and turn the PC back on. You'll notice maybe the boot order will change, you may have to go back and put some of your BIOS settings back the way they were, i.e. boot orders, turn on SMART monitoring, etc.
