To remove SUSE you should just delete and format its partition. I'm not sure if Windows will see the partition and let you do this, but there are other software packages available to do that.
From the research I've done, I think that you'll need to create a startup disk for Windows do enable you to boot to DOS rather than straight into Windows. From DOS, you should type "fdisk /mbr"
I haven't actually had to do this, so you might like to wait and see if anyone has more information.