Playing on Win 7 64bit through Steam w/ -opengl 'fix' (even though the overlay doesn't function correctly) and playing in windowed at 1366x768 on a desktop of 1600x900 w/ 296.10 nVidia drivers. Basically, if I go in and out of the window enough times over a period of time (I'm not sure there's any rhyme nor reason), the cursor will stop displaying in-game. The game still functions, tiles can be highlighted and so on, but the cursor itself will not be visible. Exiting to the menu doesn't work, minimising the window and bringing it back doesn't - only fix I've found so far is to restart the game. That is all, really.
What GPU? *Edit* Errr. What exact GPU. It is clearly an Nvidia GPU. Presumably a Geforce of some model. And is it integrated or a add-on card?
I have had this happen too (albeit not with opengl). Making the game lose focus again and switching back to it a few times can let it display the cursor.
Worked out how to 'fix' it, or should I say how to get the cursor back. I cycle through the Alt+Tab 'bar' until I get back to DoD and at that point it shows the cursor again. I think Kaidelong was right about it relating to the game losing focus.