I think you may have 'hosed' your vista installation, you're looking at reinstalling that again. The problem is vista uses the
ntfs file format, GNU/Linux does not natively write to this type of partition. Most Distro's will offer to
shrink your partition so that you can
dual boot between the two operating systems.
Mandriva 2006 is an old distro, I would suggest you download either a 'live' distro such as
Mandriva One Spring (32bit):
http://www.mandriva.com/en/download/mandrivaone,
PClinuxOS:
http://www.pclinuxos.com/index.php?o...tpage&Itemid=1 (this one is based on Mandriva) or the current non-live
Mandriva 2007 Spring (32bit):
http://www.mandriva.com/en/download/free.
The advantage of using a live distro is you can try out GNU/Linux without making any changes to your hard drive, if you later decide to install an icon is provided on the desktop which will launch a
wizard to assist you.
Reinstall your vista then choose one of the above options.
BTW: There are other distro's live and otherwise, the above has been suggested because you have already tried to install Mandriva.