Install windows first. It will write it's bootloader to the MBR.
Install Linux second, being careful during installation to install grub to the MBR and not the to the root parition. Linux should detect windows, and correctly write a grub config to show both windows and Linux in the grub menu on power up. You should then be able to boot either one.
Had you not wiped both OSs, we might have been able to help you fix the grub config to boot windows, with a little info from you about partitions and the contents of your grub config file.
Last edited by bigrigdriver; 09-20-2007 at 08:09 AM.