App store doesn't work, and neither do my snow leopard or leopard install discs

Thank you for listing all the troubleshooting you have tried. Makes things so much easier.

Try the following:

Disconnect all devices from the computer then do the following:

Boot up from your system DVD (the one that originally came w/your iMac) while holding down the "c" key.

Select the language you wish to use, and then choose "Disk Utility" from the menu bar.

Your HD should appear in a panel on the left hand side of the window which opens. Select it and then click on the "repair disk" button in the right hand section of the window.

Once this process has been completed restart your computer and repair permissions directly from Disk Utility.

If Disk Utility is unable to complete the repair, you will need to use a stronger 3rd party utility like DiskWarrior, Techtool PRO (not Deluxe) or Drive Genius.

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Make sure the DVDs are not dirty, smudged and/or scratched.

http://support.apple.com/kb/TS2000Mac doesn't start up from install disc

http://support.apple.com/kb/HT2801Apple Computers: Troubleshooting the slot-loading SuperDrive

*** Your drive may need cleaning. Cleaning kits can be purchased from any store that sells CD/DVDs. ***

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Memory: 2 GB

Max out your RAM. Download Mactracker, look up your model iMac to determine the max amt your model can handle.

How large is your HD? How much space do you have left?

Make sure you meet all of the requirements for Maverick.