i read that since the core i3 range has inbuilt graphics, so using it on an H57 board will mean that sli/crossfire will not work. i dont know much about sli or crossfire,only that it helps to use multiple GPU's together for better graphics performance.
my question is that if i buy a core i3+ H57 and put only ONE Graphics card in it, then will it work?? or does having a core i3 on an H57/H55 board means that iv killed my options of upgrading to a graphics card in the future? :(
please help... iv searched a lot on the net, and the answers are quite confusing.

Yes, you can install a dedicated graphics card, if there is a Pci-e x16 slot on the motherboard.
But you might have to disable the onboard graphics support in the bios, for the new gpu to work (and drivers install) properly.