If you got this problem with multiple games in a similar fashion, it’s quite likely that something on your PC is blocking vorpX. There are various kinds of programs that also hook into games, not all them are obvious cases. Try to disable/uninstall all such software. A few examples are:
– Additional graphics driver software that you might have installed. For example: MSI Afterburner, GeForce Experience, Lucidlogix Virtu
– Video recording/streaming software you might have installed. For example: Fraps, Dxtory, Open Broadcaster, Splashtop
– Chat programs that can show content over DirectX, like Skype, Mumble, Evolve, X-Fire
– The Steam/Uplay/Origin ingame overlays
For WOW please also check whether switching from 64bit to 32bit or vice versa makes a difference. Normally both should work, but in some cases one might work better than the other. It’s also best to use DirectX 9 instead of DirectX. You can change these settings in the WOW launcher.