I was trying to reinstall the factory preload on a HP Pavillion dv7-1245dx running Vista 64 and the computer shut off half way through the process. Since this happened, I get the "BOOTMGR is missing ..." message. I have the disks from HP and I still get this message, I can boot with a usb flash with "active@ boot disk creator" loaded on it. This boots and I can see the drive (I've done all the drive checks and all are ok). It seems likely that the hdd partitions might be f...'ed up and information is gone but I don't can, I have it backed up.