Benefit from my ignorance of Vista

FSX became progressively slower despite defragging on an automatic weekly basis. I uninstalled and installed FSX on several occasions but, after an initial improvement, the same problems cropped up.So I called for professional help.Eventually he found the cause and it was simple. My machine had been set to turn the Hard Disk off before the defrags were complete despite Vista informing me that defrags had been done each and every week.Now the problems have disappeared into the Wild Blue Yonder. I hope this helps someone facing the same problem.Cliff