Hi there unvi$ible,
This can get a bit complicated
The first password you might encounter is the "BIOS" or "power up" one. This is set in the BIOS and can generally be erased by removing the battery (I recommend 24 hours these days, although it used to be only a few minutes) with the mains supply disconnected.
Otherwise there might be a jumper switch somewhere on the motherboard (seems to be rare these days?)
The next one is the "administrator password" which is also set in the BIOS. This is to stop unauthorised adjustments to corporate machines for the most part. If you can get it to power up just try flashing the BIOS with the latest version and this will clear it.
Then you have the Windows administrator password which is in your operating system.
Please try this:
The last password you might encounter is on the hard drive (normally only on laptops)............. buy a new hard drive........... they are pretty much not worth the effort of trying to crack.