Hello Jua83100n,
The Intel® Core™ i3-540 Processor comes with Intel® HD Graphics therefore there is not needed to use a video card.
In the other hand, the Intel® Core™ i7-880 Processor does not have integrated graphics so you would need to add a video card to your system. That could be the reason why there is no video.
http://ark.intel.com/compare/48500,46473
I recommend you contact the motherboard’s manufacture so they can let you know if the I7 processor is under the list of supported processors.
Regards.