Ursprünglicher Beitrag von: mayer ,
Shut down the computer and unplug it for 15 seconds, replug and then press the start button, it may have gone into diagnostic mode and that will cause the fans to run at full speed. Next try booting from your DVD and go to Utilities -> Disk utility and unmount the hard drive and see if the fan persists. Reset the SMC: http://support.apple.com/kb/ht3964 Boot to the ASD by inserting your system installation disk and holding down the D key upon restart. If the test fails, replace the component it tells you failed.