This is a bit late, but I've just seen this thread.
At this point, you've probably reformatted and reinstalled, but just in case, where are you at in the troubleshooting process? When you try to boot the machine, what happens? Do you get a bootloader and then it fails to boot, or is there a "no disk found" / "no operating system found" sort of error message?
What you need to realize is that in most cases, the partition table may still be intact, but the bootloader is corrupt or missing for some reason. I can usually get these up and running again using either the Windows boot disc (in "rescue mode") or a Linux boot CD of some sort (sysrescuecd, Slackware, Ubuntu live cd, etc) and rebuild the partition table as well as the boot loader.
Let me know if I can give you a hand here.