How do you react when you kid says no to every request?

I have a seven year-old who is going through a phase where no is his answer for everything I tell him to do. I tell him to pick up after himself the answer is no. I tell him to get dressed the answer is no. I tell him to shower the answer is no. You get the picture. That is then followed by a ten minute power struggle while I try to force him to do what needs to be done. Which is usually followed by a complete meltdown from him. This is the first time I have experienced this on this scale and I feel like my toolbox is empty!

As a bit of background, his father and I were divorced a little over a year ago and this might be a delayed acting out type stuff. I have tried to step up my alone time with him and give him lots of positive attention, but it doesn’t seem to be having any impact on this particular situation.