OK, I'm glad you managed to enter the BIOS... at least, some progress...
My advice to you is - DO NOT CHANGE ANYTHING ELSE OTHER THAN
ENABLE USB LEGACY SUPPORT !
I'm serious, you can do some serious damage... not physical though, but you may make some changes that will prevent your system from booting. Even that can be easily fixed, but you really don't need additional troubles...
Cheers !