vista just wont start up

i installed vista home premium on my computer, but during the installation,
it restarted and then once it came back on, it wouldnt continue the
installation, i tried and tried again, but nothing. so i installed it on
another hard drive in a different computer and put that hard drive in the
other computer, and it wont start up, even though its installed and working
and activated. the other computer that i actually installed it in is a older
computer, with older parts, and the one im trying to get it to work in is
almost completely new parts, so it should be vista capible, 3d connect ati
radeon x1550 graphics card, asus p5n-e sli motherobard, 3 gigs ddr2 ram,
adaquet cooling, i just have absolutly no idea why it wont install or work.
please help