Cant Find source of Noise!?!?!

Recently within the last few weeks I noticed at red lights and stop signs while in drive when I was completely stopped, I would hear this type of whining in the engine compartment. so the first thing that came to mind was the pulley's could possibility be going bad. figuring that this was the issues, I went ahead and replaced all of them both tensioners and idler pulley's. Unfortunately that wasn't the issue, in further inspection I had narrowed the problem to the alternator. after spraying liberal amounts of lithium grease into the alternator were the bearings are located the whining would go away but quickly return. leading me to believe that the bearings within the alternator were going bad as well. After replacing the alternator and pulley's the noise is still present. the noise is definitely not coming from the compressor so the only thing other than that would be the power steering pump. which I might add, has been leaking ever so slightly lately. Also ever since I purchased the car the power steering seemed to be a little on the weak side. with that being said could this be my problem? or am I overlooking something.