im having the same problem and am totally confused, can someone help me

so i have a pantech burst and i rooted it and all was good i downloaded this app to be able to look at root files ect. well using this app i changed the font on my phone or thought that's what i was doing! when my phone rebooted it is now stuck on the rethink possible screen! i have been looking every where online and cant find anything that helps! my computer recognizes my phone but the usb debugging is not on and i cant get to the settings! i can see my phone in device manager but that's about it! i don't know what to do and im extremely frustrated! can anybody help?????

The power button and the volume keys of my pantech burst is gone and i cant switch my phone on..and another problem is that it startup showing pantech and goes and then again repeats when plugged in charger..when we off the charger the screen oftern went off..i have replaced it with a new battery about three months ago..i think it may be the problem with the android os..

please give me a effective solution to this...