I was getting fairly regular BSODS on windows 7 and couldn't figure out why. I thought it was the controller drivers and hunted for the latest but no luck.
After more research, it seems that sata controller cards/ external docks / and the WD drive 'intelli' features cause the drive to stop responding and bsod the system or just drop out.
I'll never again buy WD green drives with 'intellipark' 'intellipower' etc .
I just swapped the drives with seagates and all works just fine now--the WD drives are now for backup only. I guess it was my fault for being cheap :)