hi, my sister's white 2007 macbook has been acting up a lot lately. - it shuts down when the you close the lid (ie. doesn't sleep) - every 5 minutes or so it makes a sound as if it was loading a cd/dvd - now it takes about three attempts to actually turn the computer on (and takes ages to boot up) - freezes when you try to restart the computer - we just tried to attach an external harddrive, however it is now not being recognised (just in the past couple of minutes). Nothing is being recognised as being attached to the usb slots. It is still in Applecare warranty so I will take it into hopefully tomorrow, but just wondering if there is anything I can do now to help it, or what the problem may be. I checked the hard drive in disk utility and the SMART status said 'verified'. The harddrive was replaced in the macbook about two years ago (the first one just died suddenly). Does this mean another HD failure is imminent? (I'm a bit concerned because now we can't back it up since it won't recognised any usb/external harddrive). It's running Leopard 10.5.8 (i think). Any help would be appreciated. Thanks!