It really would help if you could give the version # of mandriva .http://www.mandriva.com/en/
Many current versions of Linux have the option of booting the CD 'Live', that is to say, running only from the CD.
If so, you can do that and look around and see if you can find whee mandriva was installed. But the XP install may have wiped it out altogether.
If you drive is big enough, like over 40 GB, you could install both systems on the drive. XP has to go first, but use only half of the drive.
You are certainly welcome on this forum. May I suggest your also try a chart room on any of the Linux forms. The Ubuntu community is very active non the chat.