Congratulations, sounds like you've got a DeathStar...
According to some specifications I found:http://reviews.cnet.com/desktops/emachines...7-31466283.html
and the illustrations in the maintenance guide:http://downloads.emachines.com/userguides/...s_HW_ref_en.pdf
the system has one ATA100 controller and one SATA150 (SATA I) controller, so it looks like you should be able to fit either IDE (ATA) or SATA drive. An ATA133 drive will work fine on an ATA100 port, it just limits its speed to ATA100. Most SATA drives are now SATA300 (SATA II), and will also work on a SATA150 port, some adjust themselves, some have a jumper to set them back to SATA150 speed.
Further resources for that model here:http://www.emachines.com/support/product_s...amp;model=T6410
By temporarily fitting the new drive, you can use suitable software to "clone" the current drive (as long as it lasts). Ghost or Acronis TrueImage are the two most commonly used - I use Acronis. Most hard drive manufacturers provide software to do this, so you should not need to purchase unless you want to.
I use mostly Seagate drives, and they provide DiskWizard
and if you get a WD drive you can use Data LifeGuard
The simplest way to have a restorable backup in case of OS corruption is to use the drive management software provided to create a backup image, and have a bootable CD or DVD to restore the image if there's a problem. I have all my systems backed up this way, using the Seagate DiskWizard, which is a limited edition of Acronis TI.
Edited by Platypus, 03 January 2009 - 10:28 PM.