Going to run my defragger and check to see how large a partition (+ swap) I can make and if it's not around 10 gigs or better I'm going to take my nightly nap.
Now I'm confused....All this time I thought you were unable to boot into vista.
note:you don't want to use the auto installer.Trust me.When you get to that point edit the partition yourself
With jaunty people have had bad experiences letting the installer do the work for em...over writing their Microsoft partitions.(this is that 1% were linux might not do what you ask
)So use the installer,and edit the partition manually.
You probably lost the space from vista backing up restore images.
During normal use a microsofts os will make backup images(not everything,but just system folders.) without the user knowing.It can be shut off,but is not by default.Over time theses images will eat hard drive space...without a user's knowledge.
edit:I should add that you should turn it off,and delete those recovery files if your trying to gain disk space.There always put at the end of the drive,and will continue to do so....but be warned it might not go as planed...but what does anyways?If there were no surprises life would be boring.
something to read...Its interesting,and I do not condone it.
But you can make your own using an app called nlite,and its all legal to do so.
http://www.davidtan.org/tinyxp-and-tinyvista/