Problems on Start up

CCleaner for Windows
1

Ive been looking at a friends computer this afternoon who after installing CCleaner found that the after entering password it would take about 5 minutes for the computer to start up and display the desktop.

Eventually I told the CCleaner program to run on start up and now it boots up fine.

I was wondering if anyone knows why this would be the case as normally a program will slow a computer down if it runs on start up not the other way round.

2

it might due to windows update doing something in the background

when you do the next restart, its already finished

or prefetch folder being cleaned