Blank screen when using new graphics card

Hello to everyone reading this and thanks for taking the time to help me out

I recently bought my cousin an old lenovo m58p to modify into a budget gaming pc , now first of all this motherboard was a form factor ive never seen before as it was made to fit into the small form factor desktop , but i managed to modify a brand new mid tower gaming case to fit into , i had also bought a 500w ocz power supply (brand new ) and an asus eah5830 1gb ddr5 direcT cu2, now the problem is that the asus card wont work with the pc , i plug it in ,switch from integrated graphics to pcie graphics in the bios and then restart the pc and plug the dvi cable into the asus card , buy all i get is a blank screen , it does not give any signal to the monitor , and smetimes when i do this i get a beeping code, it beeps 3 times and then beep twice and repeats the beeps once more , i can verify that the graphics card and psu work as im use them in my rig for testing purposes , but my cousins pc only works off of the integrated mobo graphics and i cant remember exactly but i think i got his pc to work with a low endgraphucs card that doesnt require external power, any ideas ?