Recently I was surfing the internet and an ad came up. Immediatley the screen went black but the computer was still on. I held the power button down and the computer shut off. I tried to turn it on again but right after the login screen it went black and just shut off by itself. I was thinking it was either some type of bad virus or just because I have had the iBook for about 4 years. Please send some knowledge my way about this situation. THank You