Attempting to recover Windows partition

A computer in our house had crashed "randomly" after attempting to load an application. On reboot, Windows reported that system files were missing. This is the second time this problem has happened in about two years (first time was fixed by repairing the windows install with the recovery cd), but the recovery cd wasn't available this time, so I tried to fix a couple things, which led to the computer not being able to find 'ntldr.' Also, the recovery console displayed only 3 files in the whole filesystem afterwards.

I loaded Knoppix in order to look at the NTFS filesystem on the hard drive, but I only see about 50 gibberish files scattered in the root folder. The mount command shows the hard drive mounted as 'vfat,' but any attempt to modify it results in "the device is busy." qtparted shows the drive containing an unknown partition format. TestDisk shows only 730 MB on the hard drive, despite the hard drive containing around 160 GB maximum capacity. fdisk -l doesn't display anything. Any ideas on how to recover this hard drive?

gpart (which is included in knoppix) might be useful for last-ditch rescue attempts in cases where it appears that the partition table of the disk is lost or corrupted.

Gpart attempts to guess the available partitions on a disk, and if you agree, you can instruct it to write a fresh partition table onto the disk.

However, read more about gpart before using it: http://www.stud.uni-hannover.de/user/76201/gpart/

Good luck!

{TestDisk shows only 730 MB on the hard drive} that is not a good sign.
Does the bios show the correct hdd size ?
IF you do not know how to use TESTDISK go to its web site, I guess gpart does about the same thing.
http://www.cgsecurity.org/index.html?testdisk.html
TESTDISK can be use in pure dos (Win98 boot floppy)

might want to go to hdd manufature site and get it's test utility and run it.

Is the hdd an IDE or SATA?