Do you know what type of partition the windows system is on? I assume this is Windows XP we're talking about. Usually Windows XP partitions are ntfs. This website gives a quick step-by-step on mounting ntfs http://www.linuxforum.com/tutcomments/1/688.php

Note: These instructions make the partition read-only. It is possible to make the partition read/write capable, but last I heard, this is still unstable and therefore could cause damage to your windows setup. Unless you really have to, I would not make your ntfs partition writeable

Hope this helps