the best way is to always have a live cd....
you need to know your x,y as per my signature.
windows is likely to be on first partition which is (hd0,0) so linux is on something else.
if you do not remember how you partitioned.....the live cds have partition tools included
gparted qtparted fdisk cfdisk sfdisk ....you get the idea
and for beginners qtparted will give a graphical view....but do not click on apply button...which makes changes...so go in and have a look ...write down details and post back pls