sometimes there can be glitches like that.
To me your spec means you can play the game fairly well. If steam verify doesn't work then it could be a corrupt file. You could try a Windows re-install, it's always good to do once in while anyway. But it's a pain, as you have to re-download everything again. Have you tried re-installing the game. As in removing and doing a fresh download?
If not try that, and then if you've no success you can try the Win re-install. Make sure all drivers are up to date first, GPU/Chipset, BIOS, etc. Rule out the simple things, before a system reset.