Opening photoshop?

maybe the wrong place for this question, but i figured the peole in here would have the most exp with it.
I just got this message when opening photoshop cs. Its never happened before.
“memory could not be allocated for the activation process. Please close all applications and try again”.
i installed yahoo messenger recently, but deleted it. i defragged my comp and deleted all the bs programs that i need.
after doing all this i restarted the comp, and it doesn’t look like anyting is sucking up too much ram. ram really shouldn’t be an issue. i can open up painter with no problem. illustrator as well. hell both at the same time, but no photoshop.
anyone know what might be up?

tried reinstalling photoshop?