Public libary file won't open on my Kobo Aura H2O

I try to un install - install version 4.5 /3/2 and no matter what, I can read the file from my cumputer but not on my Kobo even if it's autorise.  A cannot count the number of time every thing was uninstall and install both on my kobo or my PC.  Could my PC be too old? Do I need to switch my Kobo for a Kindle?  Please help me.