Well hello there, I've been having this issue for a long time i have old iMac not very old but somewhat old it has the osx 10.5.8 which i think is leopard one. I've tried doing research first to fix it and now I have a different problem so let me explain. At first when I would start it up it would go to the apple logo screen that loads then it goes to a blue screen which would change its color to a darker blue and change back to a lighter blue and wont ever go to the main screen, i have left it on like that for hours and no change. After doing some searches and stuff I found out that the main reason that this occurs is because of ApplicationEnhancer and I need to delete that so I booted my mac using cmd+s which would make my mac go to a black screen with white codes and I did the exact codes that had to be done to delete Application Enhancer, the instructions i did are these: Reboot into single-user mode (hold Cmd-S while booting machine) Follow the directions OSX gives you when you get to the prompt ( just type /sbin/fsck -fy ) Remove the following files: rm -rf /Library/PreferencePanes/ApplicationEnhancer.prefpane rm -rf /Library/Frameworks/ApplicationEnhancer.framework rm -rf /System/Library/SystemConfiguration/ApplicationEnhancer.bundle rm -f /Library/Preferences/com.unsanity.ape.plist Exit, to continue booting normally And after I typed exit and pressed return or enter button on the keyboard it went back to a blue screen but this time the cursor was showing and I could move it and about every 3-6 seconds it would go back to a black screen and the black screen sometimes would be for like a tenth of a second or a second or 2 and it would show a few white codes which I cant read it cause it keeps going back to the blue screen immediately and it keeps doing that, I was told to wait a while but i've been waiting like 30mins and nothing has happened still the same thing. If anyone can even try to help me, I would really really appreciate it. Thank you and thank you for reading and taking your time here.