Thanks for your replies!
I inserter some books through, amazon, via kindle email and calibre...
Just now I found the kindle stuck on the screensaver with the light on and almost all the battery gone...
I guess it could be some badly formatted books, problem is I have some 60 books in it... Good luck finding the bad one
I guess best option is to try reinstalling the os, I will have to look if there is any advantage or problem to update to the newer os...
Thanks again for taking the time to answer!
I will try to update this thread to let you know if I make any progress
