Strange little problem: WD3200AAKS Caviar Blue

WD Internal Drives Desktop & Mobile Drives
7

I obtained A Blue Caviar WD640 to replace a seagate 500GB @ system wouldn’t recognize unit & other times it would. I called retailer &  sent unit bak. They told me they installed windows(?) with no problem & returned unit 2 me. I finally removed or HDD’s & was able 2 install XP Pro,  would not allow Win 7, but once I reconnected other HDD’s the WD disappeared. I mounted in an external enclosure device & it was detected again with XP Installation. Put it bak in case & yep it disappeared again. I switched to new sata cables, bios (Gigabyte GA-MA790FXT-UD5P) is up to date, tried resetting 2 default & optimization, pulled memory & reduced to 2gb have 8 installed, tried using other power cables from PWS. Nothing works. So  in spking with Gigabyte tech, He mentioned that mine was not the first call about having difficulties with WD HDD’s.  My only alternative is to return unit again & wait for a seagate which I know works cause I had a dual boot system until it died.