Instructions
Download and install PCSX2. Add your BIOS (SCPH-XXXXX.nvm, where XXXXX represents the BIOS ripped from your PS2) to the "\plugins" directory of your PCSX2 folder.
Start PCSX2 and it will bring you to the configuration screen. Click the middle button to configure BIOS, then from the pulldown menu, select your region and BIOS that you want to use. Configure the other settings, then click "Apply" or "OK" to finish.
Launch PCSX2 after configuring the BIOS, then click "File" and "Run CD/DVD" for any standard PS2 game of the correct region. If the game loads, you'll know that your BIOS worked.