Okay, thanks for all the advice.
I tested with another SD card and still a bit slow, but doesn't lock up.
I have some bad Epubs that I removed, and that helped.
Still not happy about the screen's response; seems very slow (all this long press business) compared to my Ipaq touch screen. If I peel up the screen protector at the bottom where the tab is (loose anyway) and touch the screen, it's definitely more responsive but still not as fast as I'd like it to be.
I tried txt files and html files and my Glo can't read either. It opens them as though it's working and then all I get is blank page after blank page.
Does anybody know why Kobo Glo has a problem reading txt/html files? Is there somewhere I should be placing them? I read about creating a document folder and I tried that but still they just appear as blank pages.