I have been running into a bit of an odd issue with my G5. So I was running OS X Leopard and applications began to stop working like Software Update and other core service applications. I proceeded to try and repair both the volume and permissions in Disk Utility but was met with "Underlying Task Reported Failure" as described here. I figured I would simply erase and install since the steps in that article did not do anything. I booted off my Leopard 10.5.4 disk, went to Disk Utility, and completely erased the whole hard drive with Zero Out Data. I then reloaded OS X Leopard and all seemed well. I got it up to 10.5.8 and began to reload my applications and data. I went to install iWork and iLife and was met with an odd error. It was stating that the programs were open though iWork and iLife were never installed. I then installed Office 2008 and wanted to update it, but the SP1 update says it will use only 8 KB of disk space and never installs. I can repair permissions and the volume as normal in Disk Utility. My question is, does this sound like hard drive failure though most testing software (SMART Utility, Apple Service Diagnostics, etc) report back fine? Is there a certain free hard drive testing software that anyone highly recommends? The drive in question is a 1 TB Western Digital Caviar Blue with 4,503 hours on it. Maybe this is all a coincidence and I should just erase and install again?