vista is turkey gobbles hd partitions

Vista has thrown a curve ball at me. I installed Vista from CD onto a clean hard drive. Therefore, I chose the 'Custom' installation as the 'Upgrade' installation was not available.
I had 152625 MB of available space on this new 160GB hard drive. Of course, Vista installation default wanted to install Vista onto all of these 152625 MB partition.
But I had other things in mind -- I wanted to roughly partition my drive 50% for Vista and 50% for a future Linux install. So I typed 76313 MB for my Vista install partition, creating that partition in the unpartitioned space.
Vista did a great job installing on that 76313 MB partition space! But now I can't find the OTHER 50% of the drive. In Windows Explorer, it only lists one volume (the 76313 MB sized volume). I can find no access to the other volume to format it.
Can anyone help? Thanks in advance.

From the original post author -- NEVERMIND, I found it, and formatted the second partition. What had fooled me was the new Aero Interface ... the unformatted volume was listed to the RIGHT of the C: drive and I kept looking DOWNWARD when using the GUI for Windows Explorer. Doh!!