I noticed something intruiguing during the start-up process on my new Z18 PC.
The WiFi dongle flashes randomly all the time (it is not an idle condition), as it is trying to communicate to the world, even if it should not be already operative.
You know, I'm just a little paranoid 
BTW: a startup time of 1' 30'' is normal and acceptable? (with my previous Win7 it took around 25'')
Well first off Windows boot time was enhanced with Fast Boot plus a setting in Windows that meant your hard drive never got turned off even after powering down.
What are the specs of your machine? Also to provide us with info about your dongle please enter in a terminal (Menu | Utilities | Terminal) and enter:
sudo lshw -C network | grep -A 10 -B 10 "wireless"
and post back the results please. (Please note that if you scroll to the end of that terminal command there is a copy to clipboard icon so you can right-click and paste it into the terminal.)
You could maybe disable Connection checking in Settings>Privacy