Just guessing---when you did the hard re-start, a file got garbled. If I read you correctly, Windows tries to boot and then hangs---this indicates that something on the Windows drive was damaged (logical since that is what you were using....
One thing to try is to boot from your Windows install CD--Rescue mode, and run "fixmbr". This puts Windows back where it was before you put in Linux.
If you want to preserve the Linux install, you will need to go in there first and put GRUB on a floppy.
Let us know more about what the Linux distro is--and how you would like to proceed. We can then give more details