I have a WD External 1TB HDD, about 4years old. Recently it stopped responding, with disk usages at 100% and when plugged in the whole PC seems to slow down, apps are not responding.
Run the 'Extended' test on the drive for a thorough test - it may take a while to complete.
Well the problem is that when the drive is plugged it it tends to make all the app freeze. So I tried WD Data LifeGuard, but the application froze and there was no way around. So I unplugged it and the app ran, its a bit strange. Thinking of contacting WD for repairs.