When I open the game and select multiplayer for 2 players and select two preset teams and start with the default map the game loads fine, but, when I make my own teams and select a map and enter the game it starts to load then my screen just turns itself off, OR, the game just flashes and shuts down.

It is set in 1024x768 which my desktop settings are also set too, but when I have it in a smaller resolution in runs fine but the screen on the game is too fat and chunky to fit into my monitor so it cuts a lot of the map off (im sure you know what I mean!?)

Any suggestions, all my Nvidia graphics drivers are up to scratch.

Have you downloaded the 3.6.28.0 update from wa.team17.com?

It's download from Trymedia and i've paid for it (well me mate did!), will the patch still work or is their different rules for downloaded games?

Another Trymedia victim.

Unfortunately, the trygames version does not support the latest beta patch, which is probably the solution to your problems. Trymedia do allow refunds under some circumstances, so search for the refund form and get a refund if possible. Then buy the game from Team17's store. That's the best advice I can give you.