I have the same issue. System stopped booting, HDD - "Access Denied" when I'm trying to transfer data on other computers. Tried taking the ownership, still nothing has changed.
I've followed a suggestion on one of the Forums to boot from Windows 7 bootable disk. Te result - "Wrong operation system" which was kinda expected, but I gave it a try since it seemed worked for someone else.
Need help with recovering data/accessing hard drive before complete system re-install with data erase.