Multiframe version 21 new install - toolbars/ icons too small to see on laptop or monitor

Grateful if someone can help me. I've just purchased Multiframe version 21. I've tried it on 3 separate monitors and changed the Windows display settings but all that does is change the text font size, it doesn't increase the size of the toolbars/ icons. They are too small to see, so I can't choose the right icon, rendering the software unusable. Grateful for any advice. Thanks.