I have been using the free edition. I willl not buy this software. Everytime I run a full scan on a 240GB HD with 90GB usage, it takes 10 hours to complete. I was using Windows Defrag, but that never finished.
I have a gaming computer and it is clean.
By scan I presume you mean analyze. Analyze takes only seconds for me.
Try running in Safe Mode.
i think by scan John actually means Defrag, because (as stated by @kroozer) an Analyse only takes seconds (7 to be precise on my PC).
defrag'ing 90gib, if heavily fragmented may well take many hours.
what was the % of fragmentation?, how many files were frag'd? do you have Stop VSS option ticked?
what about restore points and hibernation file - are they excluded?