I ran Onyx using this guide:
Keep your Mac running smoothly with OnyX : Switching To Mac
However I really want to defragment the hard drive, because after digitising my complete Friends DVDs (80GB) and selecting a few choice films to digitise (80GB), a big of lag has now come up when initialising programs
I am thinking getting a spare HD, taking all the video files off then putting back on should do it, no?