Kenmore vac won’t shut off, blowing heavy air from vent

\015 I’ve experienceed four problems with my 216-37000800 Kenmore Quick clean vacuum. I bought it last July. Last weekend, I emptied dirt from canister. Then the problems started..1. I started vacuuming, when I realized that the power switch wasn’t working. I kept tapping it to turn it off but it doesn’t turn off. I tried jiggling it but still nothing. I have to unplug it to turn off (and, consequently, to turn it on..2. Also, the vent at the bottom of the canister started blowing heavy air, which I noticed because I sprinkle carpet freshening powder before I vacuum. The vent was suddenly blowing the powder heavily out of the vacuum and the powder was getting everywhere (even though I just emptied the canister)..3. It was suddently harder to push around the vacuum, even though the setting for the carpet height is always on the same setting..4. Lastly, there was a burning smell. This and the vent blowing powder around promoted me to stop using the vacuum...Help! Should I get rid of this thing? It’s only a year old.\015 – Kenmore 25512/ 25513 Progressive Canister Vacuum