Hi guys, in my job we have a Imac model power mac 8.2 with OS X tiger, the problem we have every day when we try to turn it on is that when appear in screen apple image of os x it freeze there and after a seconds the cooler of the machine start doing lot more noise and we must turn it off and take out the electricity cable and put it on again, after this the mac finally works. If u can tell me what kind of manteinment i should do i apreciate