I am not sure if you are having trouble with the SYSTEM password or the USER password. Each has a different solution. I assume you are having a Systen password problem.
I have never had this problem. I am not sure if you said that you can get the computer to display the BIOS or not. If it will display the BIOS make sure that it is booting from the correct disk by checking the setup. I think F2 is the key to enter the setup. There is a place in the setup to set password on or off.
But here are some more suggestion.
1. Go online and see if you can download a copy of the service manual for your computer. Some computer have a small switch on the mother board that will reset the password.
2. If you have your Windows CD, use it to REPAIR the installation. If all fails, you may need to reformat and reinstall complete but try 4 below first.
3. There are a number of troubleshooting software programs that work from a CD. That is they boot from the CD not from the hard drive. Can you boot into one of this type program.
4. Do you have a extra hard drive? You can get a small used one for less then $20.00 on ebay. Install it and re-install Windows. Once you get the computer working then install the OLD HD and copy your data from the old to new.