Based on your computer's manufacturer, this link
How to access/enter Motherboard BIOS
will give you the keys necessary to enter to access your BIOS.
All BIOSs that I have ever seen have an option to exit without saving any changes.
So if you are not comfortable or do not understand what you are looking at, after you access your BIOS, you can select the key to exit without saving and no harm done.
If you do enter your BIOS, you want to select the option to RESET the BIOS to the factory specs.