I have a dell studio xps 1340 that came installed w Vista Home premium 64 bit. I received the updgrade disk for 64 bit Win 7 and installed it a year ago. No issues. Today I used a Toshiba external backup harddrive with its loaded backup software to backup the machine. I let it run and when I came back it seemed finished. I realized something had gone wrong and the registry settings had been changed to reference 32 bit apps. I suspect the Toshiba backup was only geared for 32bit and has changed overwritten registry files. for example, I clicked in Windows explorer which I keep pinned to the task bar and it said: Winexplore.exe not a valid 32bit exe (or something like that). I tried opening Media Player and it said something similar. I tried Zune and it said it was no longer installed. I rebooted the machine and it now hangs at a black screen (but I have cursor) after the Windows is starting screen. I have to force shut down and then when relaunching I have the same experience regardless of choosing Safe Mode, Safe Mode with Networking, Safe Mode command prompt, or start normally. I must get all my data back before anything else. It is clearly all there and functioning. I could access files before I rebooted. Please help. I live and work in Kigali Rwanda and have no real access to technical expertise. I have the installation disks. I tried putting in the disk when booting to see if I could boot to a repair option, but that didn't make a difference.