"Unit wont come out of sleep mode."に関する回答PMU/SMU reset may help, w/o knowing which model or what software is running very hard to determine problem.
"My iBook doesen´t turn on. He make a three "bip". What´s it?"に関する回答3 beeps at startup means bad RAM or possible bad MLB. Best course of action see if you can find another stick of RAM to test in the machine that matches the specs.