Windows Partition slow and crashes when a video game is opened?

Hello,

In Short:

• Windows Partition very slow to load anything
• When i open a game my mac crashes
• Have to unplug from mains and wait 5 mins before re-plugging in
• IOS side is totally fine
• I have done virus searches and speed ups - nothing found

I have a custom Imac (specs below or more on request) purchased late 2012 and has been working perfectly until a month ago, i have a windows partition installed and is what i use to play PC Games, i have multiple games and all have worked fine with no problems. I installed world of warships and I'm not sure if thats the problem but since then my partition has been slow to load anything and once i open a game it crashes i have to literally unplug my mac from the mains wait 5 mins then re-plug it for it to turn back on? My IOS side is totally fine but the windows side just takes long to load but once its loaded up and been running for a while it isn't to slow until a game opens and it crashes, I've run virus checks and pc speedups and haven't found anything?

Could anyone help?

Processor 3.4 GHz Intel Core i7

Memory 16 GB 1600 MHz DDR3

Graphics NVIDIA GeForce GTX 680MX 2048 MB

Software OS X 10.9.5 (13F1077)