Can't get my C drive to come up after install

::I created a mess here and I hope someone can help me sort through it.
I got vista ultimate and I wanted to set it up on my computer along with
XP Pro. The Os's would be on separate hard drives. What I did was
clear out an existing hard drive and cleared out the partition so it was
an unpartitioned space. I shut down the computer with the boot disc in
it, restarted and it seemed to install fine. I selected the
unpartitioned space the installations went through all the motions and
what seemed like its last reboot it starts to install all over again. I
have also had errors like \"boot manager is compressed. I disabled the
drive that vista was installed on so I can get back into my XP program
and I get the \"boot manager is compressed\" message also. I have a
hyperthreading 3.4 ghz processer 3 gig of ram. I had heard that
anything more than 2 gig screws up the Vista install, however this one
seemed like it went all the way through untill it started reinstalling
of course. Any suggestions?:confused: ::