How do i enter bios on an emachine EL100G-02w?

I have an emachine that wont boot.i get the error lsass.exe The application failed to load properly i have tried booting in safe mode, safe mode with networking, command prompt, last known working configuration with no luck. what i want to try is to load ubuntu on to it via a flash drive.i need to get in to the bios to tell it to boot from the usb drive instead of the hard drive. thanks!