video problem with blitzkrieg,pls help

[alab]

i have been playing blitzkrieg-rolling thunder from few years.but before few weeks iv got strange bug--when i start some mission or campagne my monitor just goes black.i dont have problem when im on game menu or when loading scenario but when come the moment to show up map with units monitor goes black.iv uninstaled game and installed again but this not help.my version is 1.2.my pc-dual core inte,nvidia gf7600,1gb ram.lg monitor 19 inc.the most strange is that iv played alot this game on my pc before..iv didnt chaged anything---windous,drivers..nothing.pls help me!! i can also say that the only moment when iv seen scenario map is when i press alt+f4..just for sec before the game gone