To enter the BIOS Setup Utility, you just need to press F2 during POST (when your device is starting up). From the Setup Utility, you can reset all parameters to default.
However, if the problem is that the Setup Utility is password-protected and you don't remember the password (we've all been there), then there's a moderately complex procedure for manually resetting the BIOS and CMOS, but it will require removal of the keyboard to access a dipswitch bank underneath. To do that, you will first want the Service Manual for the device, which you can find here:
You'll want that manual anyway... details on the BIOS and configurable options are in Chapter 2 (which starts on page 34).
If you need to reset the BIOS/CMOS to remove a password, first you'll need to remove the keyboard (see page 63, although it will refer you to also see pages 52 and 56). After removing the keyboard (PLEASE be sure to keep track of all your screws and parts, and also be sure to wear an anti-static wristband), you will be able to access a dipswitch bank on the motherboard that will be marked "SW1". For location of this, refer to the diagram on page 108 - the bank is marked "3" on the diagram,
The dipswitch bank will have 4 switches. For the purpose of resetting the password, you only need to concern yourself with the first switch on the left hand side. It will most likely be in the "on" position (1); switch it off (0). Reassemble your device ONLY to the extent necessary to restart it - in other words, hook the keyboard back up, put the battery back in... but don't reinstall the center cover or put any screws back in the case, because you're going to have to get back to the dipswitch.
Now, restart your computer. Wait for it to boot the OS, then properly shut it down. Unplug it, take the battery out and remove the keyboard again, and move the dipswitch back to the "on" position. Reassemble your device, check to make sure there are no spare parts, and restart, pushing F2 at POST to get to your BIOS Setup Utility. Your password should now be cleared and you should be good to go.
Hopefully this helps... Having disassembled many laptops myself over the years, I'll say a couple of things: First, it's not as scary as it seems. Second, make sure you have that anti-static wrist strap. They only cost $5 to $15, and it can save you hundreds if not thousands in electronics replacement cost. Third, TAKE YOUR TIME. Don't rush anything... make sure you keep track of the screws and where they go (the diagrams in the service manual will be of great help... I recommend printing out the relevant sections so you have easy access, and also keep the manual for future reference... store it in the cloud somewhere so you can access it from another device). Servicing your own electronics can save a lot of money and at the same time enhance your knowledge of the devices you use every day as long as you practice patience and approach everything in a methodical way.
Have fun, and good luck!