Imac G5 not reconizing Leopard install, Need help diagnosing.

Question

Hello, my names Jarid and my problem is the following;
*_Using Now_*
I am currently on my macbook pro 10.6.5 snow leopard OS.
Background
I got an Imac for Christmas from my fathers Friend, the friend recently moved to china and left it behind.
this G5 (2 gigs of ram, 1.8 ghz processor) had tiger installed on it but while i have switched to mac about 6 months ago, I have a strong background in windows and learning as i go on mac. I wanted to install leopard on this G5 because my Macbook was leopard when i received it so i wanted to upgrade for familiarity.
One strange thing right before i tried to install was i tried to install new applications and they would just open up really quick on the dock then disappear and not work. Firefox worked, as well as itunes ect but they were already installed..(I think i may have DL the wrong OS support?? i do not know)
While installing a new program it actually started to run; i tried to DL a tiger version of an app to see if i might have been using the wrong instal(this is where i thought i was installing the wrong OS app maybe?).
The comp sort of froze, so i restarted holding down the power and got the purple folder with the blinking '?'. I figured i could just install leopard and fix what appeared to be "corrupt system/32 boot"(windows) I Bought Leopard @ best buy 10.5 and put the disk in and pressed "c".
Problem
It started fine until i had to pick a disc to choose from, there was no drive. I opened disk utility and I THINK it had 1 partition listed and the disk drive. I then proceeded to "erase" the drive considering it was already missing files anyways. I remember something though like I created "journalism" or something and the drive now showed in the "where do you want to install". I chose the only drive (hard drive 250g). I watched it for 40 minutes and then went and UG my leopard to snow leopard. When I finished, I figured my G5 would be done however the screen did not light when I used the mouse or keyboard. I shut it off by holding the power button. now I still get the purple folder with the '?' mark. When i use the disc to boot I cant see the drive again but this time all that is in the disk utility is a pic of a cd (guessing my boot disc) even though i saw the HD there 2 hours ago...
*_Things I Have Tried_*
1. I tried using terminal in the start up with the disc to find the drive, but it listed disc 0 1 2 3 with like 500 mb, I think 2 "X" amount of kb, lastly like one 7 GB and that was it no big HD listed?
2. I tried Holding "option" and try finding the drive but nothing showed up, I took the installation disc out at this point.
_*+Additional info+*_
I know Windows Xp extremely well but not mac too much and **everything I've done was done from what I've been reading offline**. Any help would be greatly appreciated. +I am still new to mac+ so if it is not windows-type ideology please explain A little more in depth for me please, thank you.

Answer 1

You might try resetting the SMU:
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computers power cable.
6. Press the power button to turn on the computer.
Or reseting the PRAM.
You can check the drive using Apple Hardware Test, which should be on one of your install discs, hold down the D when booting to it.
Did you wipe the drive when you were running from the install disc?
If the install disc works, try using Disk Utility to repair your drive, but it sounds as if the hard drive has failed.
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
Let us know how you make out,