just bought a new dell laptop inspiron 15 with windows 10. signed up for zwift, downloaded program and I have been attempting to pair with speed sensor (bontrager trip 100). computer recognizes usb ant stick both with extension cord and without. speed sensor communicates with its own readout but I cannot get it to pair. have tried all usb ports and have uninstalled and then reinstalled zwift. any suggestions?
That is one heck of a run-on sentence. 
When you do the pair screen in Zwift, does you Ant+ icon animate?
I’ve seen occasions where the Ant+ dongle was not completely plugged in. It installs but doesn’t work correctly. Make sure it is seated in the extension. It was quite a hard push at first. I remember that much.
Note that free trial does not start until it works, so no worries about that.
Good luck,
The Bontrager trip 100 will not work with Zwift. A speed sensor that can be used with Zwift needs to be mounted in a way that it detects the speed of the rear wheel, the Bontrager trip 100 detects bike moving speed.
The Bontrager trip 100 is more of a bike computer, then it is a speed sensor. I would suggest a Wahoo Blue S/C since it is duel band (ANT+ and Bluetooth) so it will work with any Zwift setup.