Not sure if right place. On win8 the ebook viewer fails

I was doing a clean up and had well about 25 or 30 books open at a time using calibre 1.18.

This normally doesn't cause a problem as I have 32gig ram but the ebook viewer crashed.

When I tried to open another book after closing that last lot I got a message
"calibre-parallel.exe has stopped working"

I closed the program. Rebooted windows. Installed the update to 1.19 and the problem persists. I am wondering if anything short of a full uninstall/reinstall will fix the problem.