Not another hardware failure! :(
 

I'm receiving messages like these at boot:

hda: task_in_intr: status=0x59 { DriveReady SeekComplete DataRequest Error }
hda: task_in_intr: error=0x04 { DriveStatusError }
ide: failed opcode was: unknown

I'm assuming this is a hardware failure. The last time I had this problem it was the drive.

Any suggestions besides buying a new drive? I think my DVDRW is going to crap out soon, too. And hardware is so expensive! :(

Most likely its the drive, unfortunately. I had some of these, much more than I wanted...
You can try to change flat cables, as a last try, as see if it gets better.

You need to reconfigure your kernel to work around the 80 wire cable. This means use either make menuconfig or make xconfig. Then compile the kernel.

Now the machine won't even boot.

I am sorry that it did not work. Try changing to 40 wire cables instead of 80 wire cables. Also do not use Maxtor or Seagate drives they have some problems with DMA which maybe is this error about. I suggest ignoring it.