When I click on Libreoffice a blue circle goes around then disappears then nothing happens. Am unable to use this app. Please inform me as to how I can use it.
Please expand your information, see:
https://wiki.documentfoundation.org/Ask/Getting_Started
Then please inform us about the missing Information.
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You could take a look into your task manager (assuming your using windows) and see if the process is (still) running or if it terminates. … Not sure if and where LO writes a startup log … But maybe someone else can help out here. You could also try starting soffice.exe from the cmd and see if any errors are printed to stdout. If did not understand a thing i said, just ask for clarification. 
no worries
Can you open it in Safe Mode? In Windows Start > LibreOffice x.x > LibreOffice (Safe Mode) >? If so, then Archive your user profile and reset to factory