Need help

i got a hp pavillion with a ati radeon 7000 video card well my dual monitors worked like a dream i have a dell 19" and a hp 15" but my hp cpu messed up and i switched to a emachine that a friend had i put my video card in it installed the drivers and got ready for my duals and only one monitor works i have went to activate the second monitor but when the screen goes blank to change settings it comes back up that i have to activate it the only monitor that will work is the one plugged into the video card it self the one plugged to comp wont work im lost i have it hooked up the same ways as my hp but no dual monitors any help???

see thats what i thought but the guy told me i dont need to do that i got one male and one female on my video card but on my hp i had one hooked to comp and the other to my video card and it work perfectlly