Hey guys, I bought halo 2 a year ago for my windows 7 pc to find out that it wasnt working due to the invalid product key bug. Soo just recently I downloaded Project Cartographer and everything started working almost perfectly. That was until I got a bit deeper in the campaign and started noticing random FPS drops every minute or so but they only lasted about a second so it wasn't a big deal. Then later I realized that every time I complete a mission and go onto the next one I get extreme frame lag. the game is choppy and nearly unplayable. So I restarted the game each time this happens and it fixes the problem. But then I get to the "gravemind" mission and it lags like all hell. I have to keep restarting the game to stop the lag. It's quite frustrating and I need help asap.