Can you give us any other info about your eMacs?
Like year and CPU speed? How much RAM installed?
You can find the original eMac configuration by opening the CD/DVD door.
The info will be either a sticker/plate on the front of the drive face or on the back of the CD/DVD door.
We won't be able to tell how much RAM was installed until you get the eMac booted.
You can't use discs that came with one Mac to boot another. Is especially true when the discs are for an Intel Mac.
They simply won't work.
Other things to check for, unplug everything from your eMac. Place your eMac screen down on a soft surface to heavy toweling. There is an access port that needs to be unscrewed.
This access is to get at the RAM modules and PRAM battery.
There's a chance the PRAM might be close to dead or is dying and needs replacement.
These half height AA batteries, usually, only last 5-6 years or so. It may be time to replace it.
Also, since you transported these, there's is also a chance the RAM sticks may have dislodge from their slots slightly.
The PRAM battery is located behind the RAM sticks. You need to take the RAM out anyway to get at the battery.
Each slot has two small levers at each end. Pushing down on the levers releases the RAM from their slots.
Br careful not to touch the gold connection pins along the bottom of the RAM when removing.
Once all of the RAM is out, you should see the half-height AA battery. Carefully remove it from the clips holding it in.
This is what you need to replace.
Radio shack has these. Made by Tandrian, they are more expensive, ($20 U.S.) I believe, but will get your eMacs up and running faster.
If you can wait a few days, you can purchase these batteries online and more cheaply here?
Once you reinstall new PRAM batteries, re-install the RAM making sure the sticks snap back in place. Just lightly push down on each stick just to insure it's seated all the way down into the slot.
Plug everything back up to the eMac and see if it will boot. Either from the main drive or from the 10.5 DVD
You really didn't ruin anything.
You need to now find, purchase and install a retail version of OS X.
I would replace the PRAM battery and, also, install more RAM.
Your eMacs can take a total of 1 GB of RAM.
OS X needs all the RAM it can get to run smoothly, so just install the max.
I am kinda of in a bind to tell you which version of OS X to find, purchase and install.
OS X 10.5 Leopard can still be found rather expensively and you try calling Apple atn1-800-MYAPPLE and ask for software sales. Tell them you have an older Mac and just bought an iPad.
They might be able to supply you with a copy of OS X 10.5 Leopard.
The reason I hesitate to recommend OS X 10.5 Leopard is that your eMac has barely over the min. CPU spec. and barely enough RAM to run OS X Leopard.
I would rather see these eMacs stay on OS X 10.4 Tiger, but finding these retail discs now are not impossible to find, just even more expensive to purchase than OS X 10.5 Leopard.
My advice, if you know any Mac users that can loan you a copy of OS X Tiger to install, I would go this route.
Use OS X Disk Utility to reformat the drive as an HFS+ Extended format ( journaled), choose a partition scheme, then begin installing OS X.
Once installed and you have any apps installed in the internal HD, buy an external FireWire drive and use it to clone your internal to the external drive using an app called CarbonCopyCloner or SuperDuper. So, if you have any issues with OS X on your internal drive, you'll have a bootable and backup copy of the OS on an external drive for the future.
Good Luck getting these eMacs back up to running condition.