Boot Errors

First errors to appear on this WinXP desktop were: "Media test failure: Check Cable" and "No bootable device-insert boot disk and press any key" and the HDD made a suspicious clicking sound. The HDD is a Western Digital 160GB SATA drive. Western Digital Disk Diags. reported that the drive was a 8.1GB drive and that it did not support the "Quick Test". Running the Long Test gave: "Busy timeout, error/status code:0134". A search of WD error codes said to try replacing the cable. I did so and the computer booted successfully a couple of times, although it paused a rather long time at the BIOS screen. I reinstalled the old cable and the original error appeared (and the clicking sound); putting the new cable back in allowed the computer to boot OK although I don't remember whether or not I heard the clicking sounds at this point...I was so overjoyed at the successfull boot. So, the computer now has a new SATA cable. I again ran the Wester Digital Disk Diags.; it reported a 160GB drive this time and the Quick Test found no errors. After a couple of successfull boots, however, I got another error: "Phoenix Disk Error: No cME signature found" (and, again, the suspicious clicking sound). A quick search garnered little about this error. After a reboot, the computer booted OK; I wrote critical user data to a CDR and I am now imaging the C partition to our NAS. My intention is to run SpinRite on the hard drive. Any help as to what the "No cME signature found" is about or how I should proceed?