Thanks a lot for your assistance, your advice was spot on!
I use both IE and Firefox, so I can't remember where the strange code came in, but here is what the problems were:
1. <span style="FONT-WEIGHT: bold">2: Getting into it</span>
Changing the span tag into a simple <strong></strong> solved it
2. <strong><font size="2"><font size="3">Week 3: More about learning</font><br /></font></strong>
How I got this strange code beats me, but anyway, merely removing the <br /> part of the code solved the problem.
It's a really useful block, so thanks a lot!