MAC will only boot in safe mode


I have a Imac PPC with a 2Ghz processor and 1GB of Ram. I am running leopard 10.5.8. Recently i woke the PC from sleep mode to find a blue screen with only the cursur working. Using the internet, I determined how to get the PC booted in safe mode. I have used all the disk utilities at my disposal along with onyx and cocktail to try and fix what I believe is a startup problem. I hae booted the PC in single user mode and tried the fskc codes, which i believe is just the same as the disk utility. Based on my computer all permissions are correct and there is nothing wrong with the HD. The PC still will not boot normally. I have even done an archive and re-install of Leopoard. From my reading, what I have done should have fixed it or at leas directed me to what the problem is. Can anyone please provide me with help trying to fix this?