My system began to lock up at times usually right after I hear a single clicking sound. Initial thought was OK the HD is about to die. So I start moving things off to the secondary HD and once that is through I decide to download WD diagnostic tools so I could test it out and see about getting an RMA. I run the quick test once and it failed. Easy enough so I run the more extensive test and it passes???

Now about 4 days have elapsed and my HD is occasionally not even being detected by the BIOS. I have to switch my computer off and turn it back on and hope it gets picked up. When it does I hear that "click" sound (now that I think about it, the noise is closer to the sound of power being switched off then it does to the click of death) and everything locks up and I have to reboot. I am absolutely at a loss if this is really a HD issue or another issue. Anybody have any ideas?
Here are my system specs:
Gigabyte GA-7N400Pro2
1 GB PC3200XL Pro
PNY GF4 Ti4200 128MB
IDE 0 Western Digital 7200RPM 60GB
IDE 1 Maxtor 7200RP 120 GB
Aspire 500W Power Supply
Lite-On 8x DVDRW
Creative 6x DVD
System is connected to a Cyberpower 625AVR UPS