I would just use the windows defragmenter it may be slower than the others but it means you dont have to download any custom applications, anyway you can just leave it going overnight. to run the windows defragmenter go to the start menu, Programs, Accessories, System Tools and Disk Defragmenter. You then select the drive you want to defrag and press Defragment
Windows defragger does an ok job of reorganising the fragmented files but isn't good at moving all the unfragmented files to the start of the disk. And I usually have to run it 3 or 4 times in a row to get all the files closer the the strat of the disk.