i have tried the help site on the forum, clicked on the the link but it keeps telling me i have an invalid thread:help:

What is it your trying to do roughly101? Just add a simple avatar?
The easiest way is to save the avatar you want to use on your computer (it needs to be a maximum of 50x50 pixles and less than 7000kb in size)
Next go to your options and to the bottom of the page where it says avatar. Click on the 'Browse' tab and find the avatar on your computer.
That should do it for you :)