Hello! Please, help me, I'm having a problem: When I first turned on my computer(when I bought this), there were very strange sounds from HDD. When the CPU Usage is more than 5% I can hear this sounds. Please, download recording of this sound from here:
http://www.filefactory.com/file/af99c2f/n/asd_wav
Please, download this and listen...
HDD Model is "ST3160815AS"

Howdy and Welcome Akka. I downloaded your wav file and listened. I run linux so I wasn't afeared of virus or malware infecting my computer. I Heard the platter indexing on the hardrive. That is that little cricket sound I think you are hearing.

Some Hardrives are louder than others. You could do a stress test on it to check it out if you so wish. Is this your Hardrive by any chance?

http://www.directron.com/st3160815as.html#caption

This link is for Seatools which you can use to diagnose a seagate hardrive.eace:

seatools didn't find any problems!!!

Well, you could do a spring clean of your Desktop with a can of compressed air.

http://www.computerhope.com/cleaning.htm