I have installed the game, and installed the Greyface-patch. But still I can`t adjust the graphics in the setup-window. It only allows me to run the game with software-accelerated
graphics. I have an intel hd 4400 card and a Nvidia GT750M card.
What I am doing wrong?

To be honest, Direct3D graphics were quite buggy for MM7 and MM8 back at their current time. With WinXP out, MM7 and 8 simply stopped working with D3D properly altogether (well, you had to do a lot of convoluted manipulations to make them run under WinXP at all). Even if someone has working fix, I am not sure you would cope with D3D bugs in Might and Magic.

Example of one of D3D bugs in MM8 back in time - all monsters share the same color palette (which also looked somewhat.. blurry). In my opinion, Direct3D experience isn't something to look towards in MM7/8.

After all, there isn't much benefit from the hardware acceleration. You get a nicer version of the fireball spell for instance, which looks quite cool, I grant, in long dungeon corridors.
However, on the downside, in monster hordes the different ranks of monsters are almost undistinguishable as Sarisio pointed out.
I remember that I enjoyed some of the better spell effects back in the days with my new graphics board but quickly reverted to software mode because of the drawback. It's quite annoying if you get attacked by hordes of monsters and have to check every single one of them with the right mouse button to identify which are the most dangerous.

Ok. Thanks for the answers both of you :-)

Then I will play either M&M7 or Wizardry 8 , bought both of them.

Espen