Hello Everyone 
I have a recurrent problem since two days and dunno how can I sort it out: whenever i click on the saved novels that I have on my pc, which used to be opened with SumatraPDF, it closes suddenly while stating that there was an unexpected error and windows cannot find a solution.
What can i do? I tried to uninstall and re-install it, but nothing works. I like the program and thanks to it, I have started loving reading books digitally 
Let’s start by verifying it’s Sumatra.
Start Sumatra, use File/Open (or drag&drop the file on the window). If Sumatra doesn’t crash, then it’s some kind of misconfiguration on your system that I can’t help with.
If Sumatra crashes, then it should show a message box saying it crashed.
In that case, try a few different files, to see if it’s limited to just a single file or does it crash with all of them.
In any case, create a bug report as described in https://www.sumatrapdfreader.org/docs/How-to-submit-bug-reports-c992bbe9c7b14c0eac5b7493228d4ce4.html.
Provide your OS version, sumatra version, the file that crashes.
You can also try pre-release version (https://www.sumatrapdfreader.org/prerelease.html) to see if it fixed the crash.
Thanks a lot for your detailed reply and explanation for possible solutions. I sorted it through downloading the 64-bit binaries pre-release version and I opened one of the installed books eventually.
Thanks again