Hard Drive makes weird noise after installing new GPU and PSU


Jan 8, 2012
I bought a new GTX560 non ti and a new psu 685 Watts. After installing them by myself and carefully i booted the computer. Everything was fine but i could hear a weird sound. I can't describe how it sounds but i will make a video and give you the link. It isn't too loud but it is annoying. The first days i didn't hear it all the time but now after 3 days i can always hear it. I removed the hard drive and booted and i couldn't hear that sound. The hard drive is cool and i have a fan next to it. My system specs are: Intel Quad Q8400 OCed at 3 Ghz, GTX 560 non-ti, psu Hantol 685 W, 4 GB Ram, Asus P5KPL-AM EPU, Western Digital WDC WD6400AAKS-65A7B2 625 GB (but i only have 596), Windows 7 Ultimate 64-bit SP1. I am worried that i will have to replace it. I don't think that it is a coincidence that that sound appeared when i installed the psu and gpu. I don't think that i made something wrong but i want to hear your opinion. Please answer my question. Thanks in advance.

P.S.: I know that the psu isn't very good and i should get a Corsair one but i had to get something with less money.
P.S.2: If you want any information that i didn't mentioned please let me know so i can tell it to you.

Link for the video: http://www.youtube.com/watch?v=RpgghujZwXo