I'm using a friends mac, which is PowerPC based and running OSX 10.4.6 I tried twice to upgrade it to 10.4.11 but it failed. Then my brother started playing chess but it froze, so he pulled out the power cable. Now when I turn it on it gets to the screen before the login screen where the blue bar would generally fill up, but the blue doesn't start at all. I have tried booting in safe mode, which made no difference, and also used fsck, which found and fixed an error but this didn't change anything. I don't have the install disc and it will be very hard for me to come by one. Is there any way I can fix this? Note: I have good knowledge of computers, so will understand technical stuff, but I have limited mac experience.