First of all, remove Boot Loader, GRUB from MBR and then delete SuSe Partitions. Its really easy.
* Boot up from Vista Installation DVD and select Repair your Computer (its below Install Icon). Select Windows Vista -- Command Prompt.
Execute this
Code:
bootrec.exe /fixmbr
bootrec.exe /fixboot
Close command prompt window and restart machine.
Or
* Use EasyBCD to reinstall Vista Boot Loader.
Vista will boot up by default on removing GRUB. Delete SuSe partitions now.