text not displaying correctly in MS Internet Explorer

I’ve just had problems displaying text in TinyMCE using MS Internet Explorer V7. The text in question was formatted using H1, H2 and para tags with a number of headings repeated down the page. The text displayed incorrectly in the tinyMCE window with the font size of the H1, H2 and para text progressively getting larger as I scrolled down the page. On the published page, all the text was displaying in a very large font and was blue (should have been black).

Tried editing the page in Chrome and it was fine – the published page also displayed properly.

Relaunched Explorer a few times and on the third attempt both the editor and the published page displayed correctly even though I hadn’t changed the text in between the relaunches.

If anyone has any ideas about what’s causing this I’d very much like to know in case it happens again – the problem occurred on a friend’s machine and as he’s new to WordPress he wasn’t very impressed!