hi i was having the same problem. i managed it by changing the hdd. you have fujitsu siemens>? because osx cant erase it and instaliantion cracks. i'v tested that wd and samsung sata hdd's are having no problem. now i instaled idneb 10.5.6 v2 ant it wors perfectly!!! still have problems with intel wifi 4965abg with integrated BT and proper shut down!! dose anyone have ideas>?