Thumbs down [Q] Galaxy Gio won't start up anymore


I have recently rooted my device to CyanogenMod 10.1 and I wanted to install a new theme, called Kitkat. But there came a fault 'Theme is not good comparised' or something like that.. So I searched the internet for a solution for this problem. So I came to change the DPI of my Galaxy Gio. I downloaded an app and rebooted then. But now it won't start up anymore.. How can I solve this problem?

Sorry for my bad English but I am from Belgium.