My hard drive is a Western Digital 120 Gig drive and has been acting strangely. It is also encrypted with PGP 9. What I first noticed was a strange grunt noise coming from the case. Like a triple grunt and it seems to be random. I could not pin point the noise but I believe that this is the drive making it. When the noise is made the computer lags. However it especially lags if a file is used of that drive but only sometimes. But what is exceptionally strange the drive works fine and loads content fast when all of a sudden I hear noise. However it is not consistent since 80 percent of the time there is no lagging although it grunts. I have been running defrag on it without errors. I am currently running a western digital LifeGuard Extended Test with out errors so far. I have changed what I thought was old power cables to new ones and added a second power supply (don’t have enough splitters). So is the drive bad? Any ideas what can be happening inside the drive in such a case? Any advice would be helpful. 
