Booting Vista

I am having issues booting Windows Vista. I have installed it successfully
with no issues. I change my boot sequence form my CD drive to boot from
external HDD (where I installed Vista, a 100gb partition you know just in
case). I have 3 HDDs one has XP on it and the other has data on it and the
third of course has Vista on a partition. My boot sequence for my HDD’s is
my local HDD, the data HDD and then the external HDD, I use this same boot
sequence all the time.
If I have the external HDD on and boot, various error screens pop along the
way of booting. The first one is to fast for me to read but I think it says
something about Windows Diagnostic. The next screen- Windows has recovered
from a serious error- (windows root) system32/intoskrnl and it gives me the
start windows normally option, safe mode. None of the options work because
it starts to reboot and gets to the point where the Windows Vista loads with
the progress bar and then restarts again. I think there may be a BSOD in
there also but it goes by rather quickly.
Now if the external HDD is off. When I boot it gives me this error.
F/Windows/system32/winload.exe (F is my HDD with all my data on it- and I
realize it is in the boot sequence but it never gave me this error before
unless if I accidently changed something in the BIOS…). Anyway a screen
promotes me with the F/Window… error and gives me an option to start Windows
with an earlier edition or use Vista. I am able to click on XP and
everything works fine like expected.
It should also be noted my external HDD is a logical not a primary drive, I
do not know if that makes or a difference or how to change it but this may be
the issue. My goal is to do a dual boot with Vista on my external or data
drive and Windows XP on my local HDD. Thanks any help in advance and if
this is very confusing because it is for me you are welcome to ask questions.