You will need to pull the cmos battery. and then press and hold the power button with all batterys and power removed. That should clear the CMOS and the passwords. The battery is generally accessable in two locations. I usually find it under the keyboard or via the memory cover on the back.
Once you have cleared the CMOS put the battery back.
It will redetect the HDD and ram. You may have to press F1 to continue.
That should do it.
If you have problems I have had to pull the CMOS battery press and hold Power for 30 sec and then leave it overnight. Apply power and let it boot. It just makes sure it is cleared.
NOTE: There were a few models that wrote the password to a non-clearable space. If that is the case there should be a jumper marked PW or CLEAR PW on the system board.
Second Note: If you used Bit Defender on the HDD then you may be out of luck and need to know the password to enter your HDD as Bit defender encripts the data on the drive.