HELP! Age of Empire 3 Lags On My [Window 7 Home Premium, AMD Athlon x4, NVIDIA Geforce 9100, 64-bit]?

I dont know why this old game is lagging on my brand new computer. Its been lagging for half a year now. [When I play on multiplayer eso online it lags terribly every 5 mins and then stop for 5 mins and goes back to the pattern of lagging] I never appear on the dropping screen, so it shouldn't be my connection. Besides I never drop out, but it just lags like this every game and people are annoyed by it, even Im annoyed by it. CAN SOMEONE PLEASE TELL ME HOW TO FIX THIS PROBLEM. - O yea the color scheme on my window changes when I open the game, but it automatically changes back when I exit the game. PLEASE HELP!