Today I copied my mIRC folder from my old WindowsXP PC to my new 13" Windows10 laptop.

https://ibb.co/T15c9KM

As you see in the uploaded screenshot, I use the standard Fixedsys font with the maximum font size 7. All the texts are very small. Also the Toolbar icons at the tops are very small.

Is there a fix for this?

Thanks.

you must have a replacement fixedsys font, as mine only allows me to select 9, and you have 5 and 7. As for the toolbar, you can adjust this here:

Alt+o -> Display , right hand side is a dropdown labelled "Buttons:". Switch this from small to large.

I'd recommend choosing a new default font to get larger text. Lucida Console is a rather nice one, still fixed width like Fixedsys with much larger ranges of font sizes.

See here for a previous discussion on this topic.