Mostly I play WGT on an older inexpensive computer running win7. Recently I started having problems with black screens and computer restarting(yes I know that that can be turned off). Long story short seems I traced it down to a failing gtx570 video card. The computer has been running fine since card removal and switching back to onboard graphics.
This is where the helpful information comes about. If you are having problems with either the flash version, or especially the NV(such as running past the ding line), for me, maybe not for you, that video card being in this machine made a world of difference. I find lots on many websites that run much slower then before. Not saying for you to rush out and buy one, just letting you know from my experience.
The machine is soon to have a gt1030 installed, it's about the cheapest available that should work just fine.