Odd "soft crash" issue

I am the owner of a 2009 model MacBook Pro 17" .. I use it for basically anything and everything, from gaming, file sharing, managing a large array of music, video, and photos. I have the laptop set on a CoolerMaster cooling tray on top of my computer desk to allow for maximum heat flow.

Being military I am stationed in Germany, so the Mac is running on 220v power right now.

Which brings me to the issue I am having, very sporatically I will run into this, I will be doing something (anything really) even as simple as just being on Skype or Safari, possibly even Warcraft, and the screen will lock up as if the APP is not responding, then the screen will flash blue for a second or two, then it comes back to the desktop, any APP that was running is now shut down, nothing is running that was running before. I can restart the APPS with no issues typically.

This issue is just making me really uneasy, and I am afraid its going to lead to a larger issue, I have tried to clean out my computer as much as possible, pushing 75% of my data to externals to keep the hard drive below 60% capacity (just in case it was too full) and I run disk utility > repair permissions weekly. But nothing has reduced the frequency of this issue.

Any thoughts? I am about to just pull the hard drive, put a totally new one in and do a fresh install of OSX (sort of treat it like a failing PC)

* another note, about a year ago I upgraded the stock ram to 8gb of Corsair DDR3 RAM. (checked at the time and the MacBook Pro was compatible with that model of RAM) but I did not experience these issues till the past few months. I have noticed that Warcraft (WoW) has began to crash much more frequently than what is "typical" for that app on a Mac (sadly blizzard doesnt put too much attention into Mac compatibility)

well, that about wraps up the issue.