My 5th attempt to install 1903 failed a couple of days ago. I even went as far as to remove the firewire and USB bus cards from the motherboard, as well as disconnecting every other USB device apart from the keyboard. All my device drivers are up to date, I've done restorehealth etc, still no joy. I suspect that I am going to have to go so far as to download disk image from MS and install from scratch. Next attempt will involve disconnecting all but the C disk as there is some indication that SATA can cause issues too.
It's very frustrating - it installed on my wife's and daughter's laptops without them even noticing.