My laptop doesn't boot, Please help!

Hello,
basically I boot my laptop up and it displays the toshiba screen where it says press f2, etc for boot manager. It then goes on to boot and just shows a White line at the top, which usually flickers but is not now and then nothing happens it doesn't boot it doesn't do anything at all. I've tried pressing all of the f keys but nothing happens I've tried putting recovery discs on but it won't boot them at all. I can't acess anything like the bios and I have even tried with another keyboard and still no luck. Nothing works, please help, how can I fix this?