how can i replace an on/off switch on a sears upright vacuum mod 116.31913?

My upright vacuum won't work..like it is not getting power to the lower unit vacuum motor or power head. I took the lower apart, and checked, and don't have 115V.

I'm trying to take the upper plactic/handle unit apart to get to the on off switch. I've taken all screws i can find, out, and the plastic sections won't come apart to allow access to the on/off switch.

Any ideas on how to separtate the handle parts to get me access?

Thanks.