Hi I have a sony Viao PCV-RS432G and the chassis fan is making a noise after about 20 minutes,I took case off and see that the fan is slowing down and then stopping after so long. I assume I need to replace the fan,but how do I know what I need to get to replace it? I see no numbers nad calling sony does no good as they want me to order it thru them and I would rather not do that If possible. Thanks ,any help will be appreciated.