When something works one day, but not the next, then something has changed. You task is to find out what has changed.
It can be something behind the scenes, like an OS update, that kills the video, or the audio driver. It can be major, like installing new software, that does something to existing software.
First thing that I would do would be to get the very latest video and audio drivers for your system.
If that does not work, then you might wish to look at Restore Points, going back to when it last worked.
There are some other things that might give you a clue as to what is happening, when PrPro does not open. This ARTICLE might give you such a clue, or clues. Or, it might not, depending on what is causing the failure to launch.
One other thing to look at, and think about is what is PrPro trying to load. VST's (often added by other programs, especially Audio programs) can bring PrPro to its knees. Watch the little line of black text, as PrPro starts to load. What is the last line, before it disappears? You might have to point your video camera at the screen to capture what is being loaded, as it can go by quickly.
To give you a bit more background on the VST's, there are basically three scenarios:
1.) PrPro goes out and finds all VST's, will load them and can use them.
2.) PrPro goes out and finds all VST's, and will load them, but if some will not work in PrPro, you get a one-time message to that effect. They do not get in the way, but will be loaded, without the message, the next time.
3.) PrPro goes out and finds all VST's, and will load them, but one/some will kill PrPro with no message.
Have you installed any audio programs, or VST plug-ins? Ones like Native Instruments will kill PrPro, as will many others.
99% of the time this problem caused by installing old outdated codecs. Ones installed hey are not deleted when uninstalling a premiere and uninstall wizard will usually keep the directory folders unchanged. So you will need to delete them manually after uninstall of the main program.