A reinstall won't touch your library and configuration, if you're not willing to risk it, see
How do I backup calibre?
But I doubt a reinstall will solve your problems
It could be a video driver issue, check to make sure your drivers are up to date.
There have been a couple of similar problems where deleting the configuration data has solved the problem, but that's a drastic step. If you install calibre portable you'll have a pristine configuration that won't disturb your installed configuration, you can then view and edit the same issues on the same epubs.
Hmmm -
reading your post again I am wondering if something is 'interfering' with calibre's cache - try relocating it using the CALIBRE_CACHE_DIRECTORY
Environment variable. Put the folder somewhere like C:\CalData\Cache
BR