I've got the same problem on my new HP. Can't install SL 5.1 at all, same i7 and an installation ends by black screen. The motherboard is HP and a chipset is Intel, probably the same H55. However, SL 5.0 works well..
wolfden: My installation ends by "setting up gdm" and then black screen but I posted it on the forum already. I hope that SL 5.2 will work with my nVidia graphics properly..