Can not enter bios after install Debian 7.1

view story

http://stackoverflow.com – My laptop can't enter bios after install Debian 7.1. few days ago I installed Debian 7.1 to my Acer 4750G, every thing work fine, till today I want to install another linux distro, I find I can't enter bios to change boot options, when I turn on my laptop, it show acer log and tip that says press f2 to enter bios, but press f2 have to effect, still boot Debian, I am confused and delete Debian partition, now it only display not operating system found, I try remove hard disk, remove coms battery, still can't enter bios I am guess that Debian write some thing to bios that make this happen. is th (HowTos)