OE HTML Mail Problem

I'm using OE 6 for email and I've developed a problem as follows:
I have both text and HTML read enabled. No problem with text messages. With HTML when I use the "page down" key the screen image moves down one line, hesitates for 3 to 5 seconds and then moves down a full page. When I use the down arrow to move down a line there is the hestitation and then the image moves down one line. When it was working properly I could hit the page down button several times and the page down would cycle the number of pages immediately. Don't recall when this first occurred or if I installed something and then this happened but it's getting annoying. Can anyone think of a solution or what I might try???

This may be a hardware problem. Check the manufacturer's site for info.