Old Template Keeps Showing its ugly face

I have no clue why.. But I have a new template, so i made that one that default.. I then took the ability to choose any other template away..
So the new template looks great.. but for some strange reason post will randomly show the old template.
I'm stuck on what to do.. me personally ive cleared my browsers cache.. in case that was causing problems.. ive even navigated the website on another computer .. still cant seem to shake the old template completely..
well i found one solution.. i went directly to the nodes.. and clicked Override user style choice and picked my style.. it works.. but i still wonder if there is an easier way