I have a Samsung Galaxy Nexus. I've once installed Handcent but immediately uninstalled it. But after that, I started receiving duplicate text messages on my native messaging app. Also, the power control seems to be lagging when I click some option of it, which was not happening before. Another thing is sometimes when I use the keyboard, nothing appears on the text box. These all happened even after I uninstalled Handcent. What should I do? How can I clean it or something? I really want my old Nexus performance back. It really became slow now. Is it because of the Handcent or is it another cause? Thank you 

I didn't install other apps at that time.. I've only updated some apps..