Q: Flashing question mark & Can't cmd + R

Hello theleonard,

I'm sorry to hear you are having this issue with your iMac. It sounds like you have been on the right track in your troubleshooting. Given that the Recovery system (Cmd + R) isn't loading and your machine predates Internet Recovery, you may need to see if your machine will boot from the original included Install disk, as outlined in this article:

Try Disk Utility

Use these steps to use the Disk Utility app to verify or repair a disk.

1. If you're using OS X Lion or later, start the computer from Recovery System or Internet Recovery. If you're using an older version of OS X and your computer came with a Mac OS X Install disc, insert the installation disc and restart the computer while holding the C key instead.
2. When your computer finishes starting up, choose Disk Utility from the Utilities window, or from the Installer menu if you're started from an installation disc.
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 Startup Disk (usually named "Macintosh HD").
6. Click Repair. Disk Utility checks and repairs the disk.

Tip: With Mac OS X v10.6 and earlier, always start up your computer from an Install or Restore disc when using Disk Utility to verify or repair your startup volume. Otherwise, you might see some disk error messages.

Resolve startup issues and perform disk maintenance with Disk Utility and fsck - Apple Support

Also, if the beeping you are hearing has any sort of repeating pattern, you may also want to take a look at this article:

Mac computers: About startup tones - Apple Support

Regards