120Hz - Working on XP, not on 7

Hey, as of late I had to upgrade to Windows 7 for other reasons, and one thing that I noticed is that it no longer supports 120Hz and gives me a "Signal out of range" exception, however, on Windows XP this never occurred and managed to do 120Hz flawlessly.

Now, as far as debugging goes, these following things were tried:

Made sure the GFX driver was the same across both systems.
Both times I also used the same GFX card (nVidia 630).
Unlocked the pixel clock rate.
Tried all VGA, HDMI and DVI.

Yeah, I'm a gamer and I cannot really play at top performance without 120Hz, any help or advice will be greatly appreciated! thanks.