Not exactly sure what's wrong

Hello, I've built my computer rig maybe about 3 years ago and it currently is going through random problems.

1. During gaming, the computer will do a hard freeze with no sounds looping or anything like that and I am forced to hard shutdown.

2. Sometimes after said shutdown, I boot up my computer again and everything on the computer looks to be running okay (Video card fans, etc.) but an image won't be displayed as if my monitor isn't picking up any signal.

3. Sometimes while doing casual internet surfing and skyping simultaneously, my computer would freeze than after 2 seconds it would hiccup back to what I was doing.

Note: It shows the hard freeze symptom the most maybe once every 2 days. Not booting all the time once a week. Hiccup maybe once a month.

My friend thinks it could be the Motherboard, but wasn't exactly sure. Below are my specs

3 HDD's in raid5
OCZ Vertex SDD
Zotac Nvidia GTX460 graphics card
Intel Core I5 750@2.67Ghz
Corsair 850 W Power Supply
2x2GB Corsair XMS Ram
Huge Antec 1200 case with all fans running

So many symptoms!

Oh and I have tried reseating both the video card and ram and still lead to problems.

 

I have done the 1 stick of ram test and the problems still persist.

 

It could be a number of things. The first place I would probably look is PSU unfortunately the only way to test is by swapping with a known good one. Do any of your friends have one you could borrow?

My next suspect would your GPU then Motherboard.

 

All drivers up to date?

 

i would be giving the ocz ssd a sideways look iv'e heard of freezing problems related to them fixed with a cold boot

next i would be looking at graphics card drivers and then graphics card itself

still not cured
i would be watching cpu temps to see if the are abnormally high
same with graphics card temps

something to chew on

good luck...