Hi I recently purchased an imac 27" C2D 4gb ram. I need to enter in safe boot but when I press SHIFT I can see the grey progress bar underneath the grey apple logo, then after a few seconds when the progress bar is completed apears a blue screen and it doesn´t go nor log in in safe boot, after about 10 minutes I had to reset the imac using power button, the very strange is that the imac log in perfectly but it doesn´t using Safe Boot, what the heck is happening???? could this be happening because the maching comes with the wireless keyboard??? please help, thanks