Vista installation, failed to boot, not way going back xp or vista

[Guest]

Today, i was so happy buying windows vista home premium upgrade for academic
only.
I used windows vista adviser to check whether my computer is eligible of
installing vista.
yes it was.
now, it seems that it doesn't boot as other people mentioned this problem.
I didn't make any recovery disc, so after installing windows vista and not
booting, i have no way to go back to xp or vista. I don't know how to prove I
actually had xp in my computer since it doesn't boot.
when I used start up recovery, it is not working, keep searching for problem
for 5 hours.
no response at all. i tried safe mode, it is not working.
I am not professional windows user, so things i have tried were only ways i
could think of.
I want to know how i can install this upgrade disc without recovery disc or
windows xp disc.( it doesn't come with computer right?)
as i typed in my product code, it seems that vista license is already
installed my non-bootable computer.
it is nightmare.. how can it be so difficult to install?? isn't this most
famous and top-selling OS in the world?? this should be fixed!!

 

[Zim Babwe]

This should help you

http://www.instantvista.com/windows-vista-upgrade.html