My experience trying to install linux alongside windows 7 has been fraught with problems. First I tried Ubuntu. I installed it right, but couldn’t get the graphics drivers for my Radeon 5750 to work right, they got somehow corrupted, screen was scrolling. I didn’t know what I was doing so I deleted the ubuntu partition, then it wouldn’t even boot windows. I eventually fixed that, but I didn’t like Ubuntu anyway, so I installed openSUSE 11.2, it worked great, giving me a menu on boot to choose between windows and linux. Then, on the third or so boot, it didn’t give me any choices for openSUSE. I don’t understand what happened. It only gives me choices between my 3 windows partitions.
Go to /boot/grub/ and look for the menu.lst. This is your boot menu. Also look to see if there is one called menu.lst.old or menu.lst~ that you can copy and paste from to get your menu back the way it should be.
I can’t even boot into openSUSE. I used my parted magic cd extra features thingy to do something to get me into Windows when it wasn’t working but it won’t work with openSUSE.
You should be able to boot with your suse install CD/DVD. 
Hello,I have been trying various distro’s and i have win 7 as well on another disk.The thing that really saved me from all that hassle is a cd i have with supergrub that can boot/give you the possibility to still boot win or linux even if you messed up something.I’m new to Opensuse as well and i have to check if it can boot win 7 without that from Opensuse menu (installed it just yesterday so didn’t check everything) but supergrub is a must have since on the other distro i tried even messing with grub/menu.lst wouldn’t work.
Hope it helps
If you boot from the install dvd, it gives you an option during the install to fix/recover your previous install.
I haven’t tried dual booting 11.2 and win7, but for 11.1 dual boot, you need to look at the first thread in this section: Fixing vista multiboot with openSUSE - openSUSE Forums.
There’s a bunch of ways to fix this exact problem outlined in the tutorial below:
HowTo Boot into openSUSE when it won’t Boot from the Grub Code on the Hard Drive
The trick is to boot to openSUSE and the use the method in the appendix of that tutorial to re-calculate a good boot menu and install it so it boots properly.