I have an Apple Imac G5 Model A1058 and cannot remember the password. Can anyone tell me how to fix this issue
Do you have your OS X install DVD? Boot from that, and there will be an option in the menus (I can't remember...it might be in disk utility...) to reset the user password.
I know it's possible, though more complicated, to so it without an install DVD, but you'll probably have to do some Googleing for that.