i can't update unity3d!

i have a problem!

one day Unity3D requested to update but I ignored the update!

Now I need to update Unity3D but when I click on Check for Update I get a message saying:
The Unity editor is up to date. Currently installed version is 3.5.0b3

how can I do to update it??

Download Unity and install it.

http://unity3d.com/unity/download/