Yesss! Sorted it
Grid won't start at all and the solution (Windows 64-bit 4GB RAM)
I bought Grid on Steam, and the game wouldn't launch. (No error message. The grid.exe process would just quit instantly.)
What fixed the problem was adding -novirtual to the startup options.
If you're using the cd version of the game, right-click on the shortcut on the desktop and click properties. On the Shortcut tab in the "Target" field add -novirtual to the end.
If you're using the Steam version, right-click on the game in the Games tab and click properties. Click "Set launch options" and type -novirtual and click OK.
You may only need to do this if you are experiencing a problem starting the game and are running Windows XP/Vista 64-bit with 4GB or more RAM.
Thanks for the tips guys