Hi, Like Pesto said PSP will act differently depending on your Computers specifications, meaning either how old is it or how big of HD, how much ram and such.
But above all that let me talk about your text issue:
Are you making Vector Text? (this will show up in your top tool bar, your choices are Vector, selection and floating) If you are doing vector text and you have A LOT of text, say a good long paragraph or two. It will take PSP a long time to respond because as you change what is in the text box, PSP also is trying to refresh what it looks like on your working image.
I got PSP9 to crash on me by doing awhole 12x12 page of vector text at once and then decided I needed to make a few changes to the working. PSP hated me at that moment in time!
I honestly feel that if PSP is not working correctly it is usually 99% of the time the computer it is on, user error, or incorrect installation.
To find out how big your computer is, Right click on My Computer Icon and choose Properties. At the bottom of that window will be your computers size info.
Vista is the newest operating system for Windows computers, which operating system are you running? Win98, XP...?
Hope that helps!