I need some help. We have an iMac at the office, but I have no idea what the specs are on it. It is an Intel machine and it has the aluminum enclosure with the black backing, probably 2 years old, and its running Leopard. It will not boot up (which makes it difficult to know what model it is). It chimes, goes to the gray screen with Apple logo and the spinning wheel starts, and then it shuts off and starts over. Sometimes the spinning wheel starts and sometimes it doesn't before it restarts. The hard disk makes a noise like its starting up and then it stops. It has been doing this for about 1 week now. So far I've reset the PRAM and tried to start in safe mode and neither works. Is there anything else I can try or is it borked?