I will guess that you installed SUSE the second time on the same partition as the first--or one a new one. What may have happened is that the second install failed to add Windows to the boot menu. I also assume that you have at least one working SUSE system.
Boot into SUSE and do the following (in a terminal):
su ....#to become root
fdisk -l ....#post the results here
more /boot/grub/menu.lst ....#Look for an entry for Windows, and post here (not the whole file)
If there is no entry for Windows, then you will need to edit menu.lst to add one. Assuming that Windows is on the first partition, the entry should look like this:
Code:
title windows
root (hd0,0)
makeactive
chainloader +1