A little Help ...Please!!

[NIGHTFIGHTER]

Hi Folks, looking for a bit of advise, im running SHIII with GW and mid way through the Convoy attack training mission my computer had a power cut..having done a re-boot of the system, whenever i go into the game, what ever i choose to do, It load then takes me to a blank screen with just the instruments at the bottom of the page and the game itself is frozen in "game Paused" Mode.....I dont know if there is anywhere within the game you can delete the last mission.....Many thanks for any advice you guys can give..Gary