Instead of defragging in Safe Mode, I use this nifty little app called
SpeeDefrag - It restarts your computer, and runs the defrag tool from a Command Prompt as you log-in to Windows, before any other app starts, then has the option of shutting down the computer afterwards.
Quote: "SpeeDefrag is the exclusive freeware program which optimizes windows xp defrag It restart your computer which refreshes the ram and then load just the defrag.exe program. This impose min load on system and therefore defragmentation speed is increased. This program will also shutdown or restart your computer automatically once defrag is over."
'tis nice