Last night, I performed the Boot-Time Defragmentation. It rebooted my laptop and defraged the MFT with no problem and rebooted again, but I got this message : Code: BOOTMGR is missing, Press Ctrl+Alt+Del to restart Yes, it deleted all of my data on OS partition ( C: ) I'd no time to remove the HDD and recover my data with my PC, so I reinstalled vista and dell factory settings and downloaded my data again and . . . Diskeeper is good, but don't run the Boot-Time Defragmentation !