Defrag error results in error

[Guest]

I am running Win XP Home edition, and have recently installed iTunes for PC.
While it was installing, I kept recieving the following error message: "Disk
Defragmenter NTFS Module has encountered a problem and needs to close. We
are sorry for the inconvenience.". I clicked ok, and the system said it had
disconnected from the defragmenter server (?), and then stopped running. Is
there a way to fix this before it gets worse? My computer has become
incrfeasingly slow and inefficient over the past 6 months.

 

[Jon]

Try defragmenting your drive fully, (and then try uninstalling /
reinstalling iTunes, if necessary)

start > run > dfrg.msc

Jon