Weird video card problem

Hardware GPU
1

Ok in my box of olde pc parts i can across this video card http://www.newegg.com/Product/Product.aspx?Item=N82E16814102582 I decided to see if it works cause it would be perfect for a no budget media pc i am building.

Well i went to test it on one of my nephew's pc when i first tried the card by itself everything came on,no beeps and the screen was getting a signal but was black,so i pun his video card back in,then i tried it in the second pcix16 slot,cause if it was  bad it would not let it boot all the way,and it booted up,and if i moved the cable from his card the this card it showed what the other card showed me.

I have never heard of this happening.

How can i get it to work by itself?

2

Clear the drivers off of his pc before installing the card and then install it 

3

Well i was just installing it long enough to see if it would work,cause i am not going to use it in his pc,but in a HTPC i am building from old parts,and it is not up and running yet, cause i am short a cpu,ram,psu.