Fix Now Quick Scan has been running about 18 hours...

does that sound normal?  I had turned the system off over the weekend, so it does often do a sort of catch-up. 

But should I turn this off and have it do a Full Scan manually instead?  Or is this just bc it is a really old PC that is running XP and it just takes that long?  (I know there is some kind of kerfluffle that's been happening...  but otherwise, everything seems to be working normally... so I'm hoping this doesn't mean it's been taken over by aliens.)

Thanks for all suggestions and input!!!