Windows 7: Black screen (not BSOD)

Hi there.
I'm running windows 7 professional on an HP pavilion dv5 1095eo. On to my problem:
Whenever I reboot/startup my computer everything starts "normally", except for the screen which stays completely black. I can hear the startup sounds and I can login to my user (again I hear the login sounds). Still, throughout this my screen is completely black. Only when I close the laptop (turn down my screen) and let it go into sleeping mode and subsequently open it, the screen goes back to normal.
This is extremely annoying, especially since I want to format my computer. But when I tried this by booting with my windows 7 disc it still goes black after reboot, which means that I really cannot reinstall anything since I can't see anything during the installation process and because it doesn't go into sleeping mode during the installation when I turn down my screen.
So, does anyone recognize this problem, and if so - how did you solve it? Please help me, I'm really lost here.
PS. I've tried to update all my drivers and unfortunately I have no saved system recovery points to recover it to. Thanks alot in advance!
/Kristoffer