Many Thanks
Thanks to all who replied to my query.
For "some1" thanks for your comments specifically - I feared it was a compatibility issue - but I'm still puzzled how I can run games like FS9, DangerousWaters, SWAT4 etc and yet not LockOn. I can even run the latest version of America's Army (albeit at very reduced graphics setings).
I just tried a fresh re-install of LockOn - I then launched the game, created a mission (in the editor), and when I went to start it, the laptop crashed and rebooted itself. I think it's something more than simply a graphics issue given the circumstances I describe in this post.
Any other ideas/thoughts always welcome.
Thx.
John