everything is tiny, all the toolbars and menus and text?  or just the tax forms on the screen?   or the fonts in homebase?

Tax forms size can be changed from within a client file  click View > Magnify All Forms and choose a %

Homebase text size can be changed by holding the CTRL key and rolling the mouse wheel

If it's your menu and toolbars, and youve got the program open to full screen, those are controlled by your monitor and display settings in Windows, you'll have to fiddle around with those and maybe reset to defaults.