Okay, so what I'm wanting to do is change a few png's in Handcent SMS such as the icon for the home screen, and the text entry box colors, etc. So I have the latest Handcent apk, changed the icon, and some colors that I liked for other things, and put the apk on my sd card. When I tried to install, it says, Application Not Installed. I'm NOT ROOTED and I read somewhere that the application needs to be signed or something? I'm not a developer, I just want to change a few colors of things in Handcent that you can't already customize in the app. Why won't it install, and how can I make it?