Short answer: You can't.
MyDefrag depends on the Windows Defragmentation API which is only available after Windows has booted.
You can try to defragment it in Windows Safe Mode or boot from a CD with Windows ("Win PE").
You can also take a look at the MyDefrag.log file in the MyDefrag folder. It contains information like which files couldn't be moved and which files are fragmented.
Also note that the SortByName script does not defragment all files. See [FAQ]Why does MyDefrag not perfectly optimize my disk?
for further information.
And btw. you're in the JK