Possible HD failure?

Good morning all. About an hour ago my late 2006 MacBook pro froze for quite a while so it had to be forced down by holding the power button for 10 seconds. At reboot, it looked like all would be normal but after boot was taking longer than usual, the display suddenly showed what appeared to be a progress bar. After about 15 minutes, the progress bar suddenly appeared aprox 1/4 full and then it just disappeared entirely. After another 10-15 minutes of just the apple and the spinning cog, I shut it down again and attempted to boot from another partition on the same drive. No dice, but to be fair I didn't really give it that much time before I grew impatient and convinced myself I needed to run DiskWarrior immediately. I then booted from an external HD running Tiger and that's what I'm on now. Oddly, the main partition on the internal hard drive is showing as an option to boot @ start up when I hold down the option key, as is the other partition on the drive, however, now that I'm booted from an external, only the smaller of the two partitions shows on the destkop.

Further adding to the mystery, DiskWarrior DOES recognize the main partition even though it does not appear on the desktop. I am currently running DiskWarrior on that drive now and it's taking forever. I have not recently installed any software or hardware updates at all, but I did inherit a battery from a family member who replaced her MBP a few weeks ago. I don't think that should have an effect on my hard drive but I thought I'd mention it.

I'm inclined to believe this is just a bad partition and not a complete hard drive failure since one partition is still showing and all the data on it is accessible. I'm wondering if I should just attempt to wipe it and reinstall, but there is some data on that main partition that I'd like to save. Since it's not showing on the desktop though, I don't know how I'd do that.

Any advice would be appreciated.

Thanks so much to everyone for reading.