dosbox's keymapper

I did that 😀

use dosbox's keymapper to assign a different shortcut to recording movies

What I'm trying to say is, I installed the 1.6 installer of Tomb Raider, but when I click keymapper, there isnt video so cant change the video 😀

use DOSBox's keymapper, not Tomb Raider's keymapper

I've already changed it in dosbox. I ran the 1.6 tomb raider installer and checked the keymapper, and no video. I tried to press the button for video, didn;t work

you access keymapper with ctrl-f1

One very simple thing to do here to make your normal DOSBox old game screen look bigger is to change your current desktop resolution down to 800x600 or if that is not possible then 1024x768. Choose 16 bit colour, refresh rate from 60 to 75hz how you like it. Apply the new setting and play your DOSBox old game again. You'll see the different in screen size! Hope this will help you as I also have similar Pc specs and Wins 7 to yours . 😀