Defragmenter program

Good morning Guys and Ladies, I don't know if I'm in the correct forum for this request. Does anyone know of a FREE defragmenter program that would be better than the Windows XP program defragmenter ? I think it would help the speed of the PC if the Flight Sim programs were at the beginning of the "HARD-DRIVE". My thoughts are : the PC would NOT need to search deeper into the harddrive to run the Flight Sim. I'd appreciate your thoughts on this subject also. [ Where am I going wrong on these thoughts ?] caveman