grub overriden by windows mbr

he all,
due to windows ‘genuine software’ paranoia, i had to restore my laptop to the windows factory setting. computer has got linux installed and before the restore, grub worked fine. now, it goes straight to windows 7, is there a way to get grub restarted.
theo

This easy, follow it carefully
Re-Install Grub Quickly with Parted Magic - openSUSE Forums