second screen failure ( hmdi )

Hello,

I have a problem wich someone can help me with.
I work already for a long time with two screens. one hdmi the other dvi.
It all work fine untill i updated my bios ( asus p5b ) to a newer version
Now my screen wich hdmi won't start up. ( LG flatron e2241)
Well it starts up untill my windows 7 screen. then it shuts down.

I tried :
changing settings by my videocart (nvidia geforce 7600 gt). when i set on two screen and say ok i get The blue screen.
i tried it hmdi also on my tv ( sony bravia ) same bleu screen.
i tried lowering resolution, also bleu screen.
i tried putting back old version bios ( asus wont let me )

Are there settings in my bios ( wich i search for ) wich i can adjust.
Or does any one has any other idea wich i can try.

Maxxius