You don't want to try to start Windows if it will not even boot into safe mode -- you need to boot into either the Hiren's boot disk start up or with a full Windows 7 disk if you have one.
If you are not familiar with the programs on Hiren's, it will probably be easier for you to just boot into Windows from a Windows dvd, not from the hdd. Then you can do a repair installation, which will basically replace windows but not delete your programs. You will, however, have to reinstall all updates.