Windows

Crysis

In the options screen for the graphics the "Very High" option is grayed-out. Is that something that only works with Vista and DX10 maybe ?

Most likely. It's something that happens in pretty much every game nowadays. Off the top of my head I remember Bioshock having an option much like the one you describe here (grayed out unless you run it on Vista), Assassin's Creed too, and I'm pretty sure Stalker: CS as well. With that in mind, it sounds only logic that a boundary-pushing game such as Crysis would have some DX10-exclusive features.

My guess is that it may not be DX10 holding you back but it could be one or some of the parts of your computer that won't be able to play the game at that level. So it sounds like the game is doing a component check and thus won't allow you to crash the game which it might do if played with the settings maxed out... they would do this to avoid you from having a bad experience with the game.

No, no it's definitely DX10 which causes this. I've played Crysis on similar systems, one with XP and one with Vista. Only Vista had the Very High settings available.

thanks everyone for the help