defrag button missing (turns grey)

[Guest]

when i right click c or d drive under my computer, and select properties and
then tools tab, the button 'Defragment Now' is grey and can't be operated any
more. but i can use the function defrag normally via either of below two ways:
1. right click on 'my computer' and select 'manage', and then select 'disk
defragmenter'; or
2. start => programs => accessories => system tools => disk defragmenter

please advise how i can turn the button back to normal.

thanks.

 

[Guest]

the os system is windows xp professional v.5.1 sp2

 

[Guest]

Fix Windows Built in Defragmenter
http://www.andreasroom.com/HowTo/WindowsDefrag.aspx