Hi! I just got second hand macbook white. For the first few weeks, it seemed well and has no problems at all (aside from once, the keypad won't respond when I am trying to wake the laptop from sleep and enter my password) but today, I noticed that there is this disturbing noise that lasted for about 7 minutes. When I opened the mac, the noise is not there and after a few minutes pfff it suddenly popped and the overall performance of the mac became so slow. After the 7 minute noise, the performance of the mac went to its original speed. The only applications opened when the noise was present are the following: safari with four opened tabs, YM, Syrinx-twitter app and a word document. What do you guys think could be the problem? Do I need to have it repaired already? BTW, mine is a 2ghz, intel core 2 duo, 1gb, version 10.5 white macbook-- if that info might help.