@sayradah you did not tell us much about the pop-ups. You should tell us what they say or look like. It is possible that you are in hotel mode, demo mode or similar. I would check the options in the factory mode. Since you do not have the original remote in order to enter that menu you need to enter "Service Mode" Press the remote -control keys in this sequence :
- If you do not have Factory remote - control
'''Power OFF==>INFO==> MENU==> MUTE==> Power ON'''
You should now see options like Factory Data etc. Check in the option table if you see anything unusual. You should also find the Reset option on that menu. Try to reset your TV and see what you get.