Hello all, my seemingly healthy mid-2010 Macbook running the latest version of OS 10.6 has suddenly become unresponsive and won't boot up past the initial grey screen. Below is a list of things that I thought were relevant: Over the last few months there have been frequent (a few times a week when connecting via USB internet dongle) kernel panics associated with Telstra Sierra AirCard 320U (https://discussions.apple.com/thread/2776956?tstart=0 ; http://www.mac-forums.com/forums/os-x-operating-system/210007-continued-kernel-p anics-can-damage-my-machine.html ) Not sure if related, as this happened when not connected (but hadnt signed out of USB modem account, which other users say could affect things). Then yesterday, having removed dongle and connected to internet via ethernet (routed through modem to AirPort): - Machine was really slow almost freezing, then froze up. Hard re-boot. Got folder icon with question mark. Did another hard re-boot and got the grey screen of death. Tried re-booting with install disk. Didnt get far until I re-set SRM and PRAM, but once booted up and using disk utilities from install disk the hard drive wasnt even showing. In Terminal it was listed as five disks of 500GB (approx.), the size of my hard drive, but couldnt get to mount from Terminal. On another re-boot (with option key) to choose start-up disk, the HD appeared, but as soon as I clicked on it, it puffed (like when you remove an icon from the dock) away. I read on a forum that a loose connection could be the fault (I just had a battery replaced at the Apple Store, so thought it could have been nudged then), so I removed and re-installed the hard drive. This seemed to fix it and I booted up from the hard drive, logged in and everything seemed to be fine. I did a backup (previous was two days ago, but good to not lose anything!) to Time Machine, ran Disk Utility, verified disk, repaired permissions, looked at the SMART status and everything was fine. Then the machine slowed down again. I opened Disk Utility again and the HD wasnt even listed and slowly the machine froze again and now won't boot up even from the install disk. Just sitting on the grey screen of death. Have reset SMC and PRAM but no response. Any suggestions very welcome! Also, any insights into whether this is a HD problem or something else. I live very remotely, so taking it in for service is not feasible, due to both time, but mostly cost. If, despite the apparent OK SMART status and Disk Utility verification it is definitely the HD I can easily get another - if it's something else, well it might be time to buy a new mac.