Problem With Clip Art On Powerpoint?

I’ve been recreating this powerpoint presentation for my aunt, and she’s requested clip art pictures on various slides. I’m halfway through the presentation and clip art technique has been fine up until now.
However, today when I tried to add pictures by Insert > Picture > Clip Art (the same way I always do it), it tries to load clip art and then just freezes until I end up shutting powerpoint down through task manager. It’s happened several times now and I need to finish this presentation! Why has clip art suddenly stopped working?