Recently, we have been watching the cpu usage on our windows 10 machine starting to climb. Most broadcasts in the past have been showing a usage of around 20-30%.

Last night, we watched the CPU usage climb to around 50%, and at one point, it hit 80%.

Then we saw the "Warning CPU Overload" in red at the bottom of the screen

What we don't understand is what changed. For the last few years, we've pretty much used the same broadcasts setups.

We have a single camera input using a capture card.
We load a PowerPoint
An intro and Outro video
A few static photos

The computer is an I7 with a graphics card

Again, we haven't changed anything in how or broadcasts have been set up. But the cpu usage has changed.

Any ideas of what to look for would be helpful

Use Task Manager to monitor as per Richard's comment. Also watch for open browsers/tabs. Some websites (often news sites) cause this behavior if you leave them open. "End Task" any programs that are showing high CPU usage that you are not familar with until you track down any culprits. Also, queued up Windows Updates will often cause these symptoms. Let Windows update itself.