Frequent Serious Problems With New iMac - Advice Needed

In early March of this year I purchased a 24 in. iMac with a 2.33 GHz processor, 500 GB HD, and 256 Mb of video RAM for the 7300GT video card. For two weeks the computer ran perfectly, and then I got the spinning beachball of death (SBBOD) while browsing the Apple web site in Safari. I used all of the possible methods for force quitting Safari and unfreezing the iMac to no avail. Finally, I did a power button forced reboot and the computer would not reboot but gave only a forever spinning black circle against the Apple Logo silver screen. I purchased Apple Care Support at the time I bought the iMac. After being on the phone for more than an hour with Apple Support, the conclusion was that I would need to erase my Mac drive and reinstall the software. That is when I learned how painfully long the process is of installing OS X from the disks included with my iMac and the importance of having a good backup.

I spent the better part of a day formatting the HD and reinstalling OS X and restoring the contents of my HD from a Restrospect backup. All ran fine for about 3 weeks. I even purchased Aeprture and began cataloging my photo collection. After three days of working in Aperture, one day I was assigning ratings to images when suddenly I got the SBBOD which never went away and once again all of the above was repeated: phone call to Apple Support, one hour plus on the phone, need to reformat and reinstall the OS and restore the contents to the HD.

After this experience, I scoured the internet for information on software for properly maintaining my iMac and avoiding freezes. I learned about the OS X maintenance routines, Disk Warrior, etc. and began instituting weekly maintenance programs to clear caches, etc. on my iMac. All went well for approximately one month. During this time I experienced no problems and regularly ran the maintenance routines, repaired permissions, verified the disk in the Apple Disk Utility, and occasionally used Disk Warrior to check for directory problems. I also ran the Apple Hardware Diagnostic and everything came back OK. After about a month I was working in some piece of software (can't remember now which software), and again I experienced a freeze and the SSBOD followed by a failure to reboot as described previously. Once again after calling Apple Support I was advised to reformat, reinstall OS X, and restore the contents of my HD.

I did so and all ran well for about 5 weeks. Last Saturday night I was out for most of the evening and came home at 10 PM and opened Mac Mail. My mail starting downloading normally but seemed to take longer than usual. When it finished downloading, I discovered the Mac had frozen entirely and I soon got the SBBOD and found no way to unfreeze the computer short of the power button reboot. This time my computer did reboot, but I discovered that I was no longer on our LAN network so that Safari could not pull up a web page nor could I download my e-mail. I ran Disk Utility and repaired permissions, and then tried to verify the disk which failed and gave me the error of "invalid sibling link". Browsing these forums, I discovered that this meant that somehow my disk directory was corrupted. I booted from disk Warrior and ran the directory repair routine three times until it reported that the directory was fully repaired. I rebooted the machine and found that I had no internet connection still even though my iPhone and my PC's were all connecting fine to our LAN system. By booting the iMac from the Apple Installation disk we could clearly see that the LAN was being picked up so there was not a hardware problem with the ethernet port. Apple Support suggested doing an Archive and Install of the software. I spent two hours doing this only to have the Archive and Reinstall fail on the second of the two installation disks. It just hung about 80% of the way through the second part of teh installation and would proceed no further.

This time I resolved to do something different than just reformat the disk, reinstall OS X, and restore the contents of my HD. I again scoured the forums here and had no problems finding many instances similar to what I have experienced. Some, but not all of these, seemed to be solved by zeroing the HD -- something I had not previously done. Therefore, I spent 2 hours zeroing the HD (to map out bad blocks) before reinstalling OS X and restoring from my previous night's Retrospect backup. After zeroing the drive, I checked its S.M.A.R.T status and it was showing no problems.

Once again I am back up and running but only time will tell if I have succeeded in eliminating the freezing and other problems I have experienced with this iMac.

If you have taken the time to read my tale of woe, I would appreciate any advice you might care to give me. I have not taken the computer to the local Apple Store because I feel they would simply reinstall OS X and then tell me to restore my HD from my nightly backup and that all is fine. I have decided that if I have another freeze that corrupts my HD and I have to repeat the process I have now done four times in 4 months, I will take this computer to the local Apple Store and insist that the 500 GB internal drive be replaced with a new drive. I really cannot think of anything else to do. Any other suggestions?

Thank you for reading and responding.

Tom