Hi,
Have you checked that you have the latest graphics adapter drivers ''applicable to your OS and your graphics adapter installed?''
I say this as there are updated drivers for the ''Intel graphics adapter'' dated 22/11/2016 if you have''' Win 10 64 bit''' or '''Win 8.1 64 bit '''installed which according to the details Fixes: - Intel bug issue fixed. Enhancements: - Improved stability of 4K video playback. There is no change to the nVidia graphics adapter driver.
Here is a link to the driver download page for your laptop and Win 10 64 bit OS. Scroll down to video and click to expand.
http://www.dell.com/support/home/us/en/04/product-support/product/latitude-3450-laptop/drivers/advanced?os=wt64a
If you have '''Win 10 32 bit''' installed the driver for the nVidia graphics adapter is dated 16/12/2015 and is the original release for this adapter and has not been updated since.