My Hoover Linx handle broke.

SOURCE: How to remove handle from Hoover 5445-900 upright wind tunnel vacuum

Hoover.com doesn't have a manual specific to your model but there is one similar which will show how to remove the upper handle from the body.

http://www.hoover.com/pdfs/manuals/U5467900.pdf

Do you have a replacement switch? If not I believe you can buy one from Hoover (the switch and/or the upper handle assembly). Unfortunately your model isn't listed on the website, is this a new vacuum? I recommend giving them a call, that would be the easiest way.

Also remember when working with electronics to unplug the vacuum. Even when there is no power residual electricity can remain in the wires. If you feel unsure, take it to a repairman.

Hope this helps!

SOURCE: How do you remove the Handle from the Hoover Windtunnel Deluxe to replace the switch?

Removing the handle assembly should be easy after removal of the two screws. It may be binding or hanging up on the self-propel cable...or the plastic may just be stuck/binding. Note that the handle slides in and out of the vacuum unit along the same axis as the two screws (i.e. slides straight off the back towards you when you are standing behind the vacuum). Try to pry it off gently w/thin-bladed screwdriver or butter knife (careful now!). Not sure about the smoking issue but you may have a severely plugged filter and the unit is overheating as a result. Check that out immediately/first to avoid fire or expensive motor burnout.