This happened to a friend, a few days ago, while I was at his house, and the feeling really sucks.

You can try a few things, but if your boot sector's gone, either the drive's completely dead, or if it's still working, you're in for a new format and re-installation.
Here are a few things you can try:
1. If you have access to another working system, connect your drive as a slave to see if it recognizes the drive and can read its contents. If so, you'll be able to save any critical files, even if you can't get the drive to boot again.
2. Download
NTFSDOS.EXE. It's a utility you can use to view NTFS drives from a bootable DOS floppy. Boot to the floppy, and see if you can view your drive and files. If so, you will be able to recover your files.
3. If you have a copy of Partition Magic, you can boot to the floppy and use it to see if the drive is still formatted. If it reports an unformatted drive, you've probably lost everything on it.
Events like this are the reason why, when setting up systems for friends (and myself), I always recommend buying hard drives in pairs, mounting one in a
mobile rack and using Norton Ghost to clone the drive.
The Ghost copy is a fully running clone of your drive so if your main drive becomes corrupted or virus infected, all you have to do is Ghost back from the backup to the original drive, and you're as good as your last Ghost. If the drive completely fails, swap out the drives and keep going. You'll be out an inexpensive piece of hardware, but you won't have to set up your entire system again.
I Ghost regularly after each virus and spyware sweep and before I install any new program. In my friend's case, it took just a few minutes to restore the drive to his last good Ghost copy, which meant all he lost was three days of e-mail. He now Ghosts his system daily.
It takes around ten minutes to Ghost my 80 GB ATA 133 drive. My friend has a pair of 120 GB SATA drives, and it takes around four minutes to Ghost his setup. In either case, that's a small amount of time for 100% security.
Windows restore points are nowhere near as safe or useful. If, as in your case, your drive becomes corrupted or dies, you have no restore point to go back to, and some viruses attack the restore point information so restoring a drive to an earlier point doesn't get rid of the virus.
Good luck.
