Formatting text -

Another option that might help you is to Click on your User CP area {up above on the left}

Then click Edit Options and go down to the bottom of the page to the
Miscellaneous Options section.

There is a box that says -
Message Editor Interface
When posting messages to the forums or other members, there are three interface types available to you. The simplest of these is a simple text box, while the last is a fully-fledged WYSIWYG editor, which allows you to format your text as you want it and see the results immediately.

Depending upon the capabilities of your web browser, you may not be able to use all of these options. If you experience problems when posting messages, try switching to a different interface type.

Try the Enhanced Interface - Full WYSIWYG editing
and see if that works better for you.

and at the very bottom be sure to click the Save Changes button.