Locate the 8-pin chip near the CMOS battery. It will have a sticker that says "MX25L..." or "Winbond 25Q..." The Process:
Turn the machine over and look at the lower casing. Search for tags such as: hsb j mv-6 94v-0 e89382 bios
Go to the official support website of your motherboard manufacturer (e.g., ASUS Support Gigabyte Support Search for your specific model identified in Step 1. Locate the 8-pin chip near the CMOS battery