CSS difficulties with IE and FF

Who thought of the idea of creating different browsers? That was a very, very bad idea!! It makes the life of a webdesigner pretty hard.

In FF I'm having no problems at all, it all works just as I want it to work. The header and the menu are standing still and when you scroll down, only the text (my reports) moves so you won't 'lose' the menu when you're reading. In IE that doesn't work and I'm now facing the following problem: Should I
- just let the complete page scroll? So if you're reading one of my long reports, you 'lose' the menu and the header. With other words: just like my website functions today.
- add another scrollbar next to the text/the content which solves the problem, but is optically not so nice.

Or, does anybody has an IEfix for this problem?

Still 70% of my visitors are using IE... poor people ;)

Ok, let me struggle around a little more...
Lets end this small frustrating message with a positive thing. Every time I see next words in the lower right corner of my browser I feel very proud: