Some feedback on this one :
I tried Power defrag and diskeeper
The first time it took me ages as it was 215 days ago I defragged.
Then I deleted some files, did some (un)installs and ran again.
First the powerdefrag and it took more than an hour to complete.
Afterwards I did the same and ran Diskeeper. It took me about 20 minutes. I must say I like Diskeeper also because you can do other things in the meantime, which is not the case with powerdefrag and you can let it run in the background.
With the few tests I did upto now I must say for the moment I prefer Diskeeper.
Thanks for your help folks