I tried that, it made the game stop working. the intro would load, then the start menu music would play but the screen would be frozen on the intro, had no option but to uninstall the game.
I've since reinstalled it, and found some options on my nvidia control panel which seems to have done the trick - I needed to increase the gamma. Slightly strange resolution to the problem, but a resolution non the less.
Hope this helps anyone else with a similar problem.
Btw, the mod packs are very unstable and some just dont work at all, the chaos one for example wont work and the wood elves one crashes on the first level. The extended campaign seems work ok though.
Thanks for the help anyways Olly