BIOS or Basic Input Output System, is an interface that had been used extensively up until the mid-2000s, when it was replaced by UEFI. Nowadays, most computers support UEFI and are much easier to work with.
The manufacturer is working to fix a vulnerability similar to a previous problem in Lenovo laptops that allows threat actors to modify or disable Secure Boot settings to load malware.
Clean installing Windows 10 is a great idea to reformat your computer if you no longer need your previous files or want to sell it to someone else. You can