Already tried running memtest86 for a gazillion years with both sticks? If either one is actually bad there should be at least some errors.

I havent done that yet, but I have tried another set of the exact same ram brand new and I had the same problems

Different set of the same brand or different set of a different brand makes no difference.
Either way memtest86 would still help.
It would rule out windows if there's still errors.
If memtest also produces errors with a different mobo then apart from some really weird PSU shenanigans it could only be the CPU.

So I ran the memtest86 for about 11 hrs overnight, and these were the results. Lots of errors..
http://imgur.com/a/jrGf2

Some other IT friend of mine said it might be the CPU, and I don't recall running memtest86 with my other mobo, but I remember reading about it at the time so I may have done it. If I did I definately got errors. I don't have my old mobo anymore though so I'm unable to swap it out and try it.

Does this mean I should look into getting a new CPU? (Kinda want to upgrade to an i7 anyways)

I'd agree with him but now I'm not sure if you actually did test other RAM.

Before you buy a new CPU there's 3 more passes of memtest86 you should run.
1. Only with stick 1.
2. Only with stick 2.
3. If you've overclocked your CPU revert back to stock settings, then test with both sticks again.

EDIT:
Why do you want to upgrade anyway? You know an i7 won't do anything for games.

Sorry for taking a few days to get back to you. Ran both tests over two days. I do really appreciate the help, Setsul

Anyways, here are the results from memtest from stick 1 and 2
http://imgur.com/a/gSKOV

Well, after doing more research, and trusting you. You are right. I've just seen/heard that tf2 and other source engine games were CPU intensive, so I figured a i7 would be better. Turns out it doesn't make near any impact.

Canadians apologising for the wait seems to be a theme today.

TF2 is CPU intensive. It just doesn't use more than 2 threads effectively (and the GPU driver uses a third one). So anything beyond an i3 doesn't help. An i7 would have twice the power of an i3 at the same clockrate, but TF2 just won't use it.

Anyway I'm assuming since you didn't do test 3 your CPU wasn't overclocked?

There's only one thing left to do now: If you haven't tested both sticks in the same slot try the one that produced errors in the slot that you used for the one that passed without errors. That rules out the slot itself.

But at this point I'm pretty sure that one stick is just broken.
That's actually good news since now you know what's been causing the problems and it's even the cheapest to replace out of all things that could've been broken.

Yeah, I tested both of them in the same slot. So I know its not the slot.

Perhaps this information doesn't matter. Earlier on in the year I went and bought the EXACT same brand new ram, and tested it. Same thing happened. Either stick in by itself, and everything was smooth. Two sticks in at once, and I would get windows memory diagnostics errors.

I understand that memtest is more accurate than windows mem diag tool is, but why would it give me 0 errors on the windwos diag for both sticks,same slot,one at a time, but errors when both were sticks were in at the same time..?

I could try that also, but I have never tampered with my CPU settings. So unless a program or something (don't even know if a program can do this) screwed around with my bios, my CPU is at stock settings already. I do believe it is overclocked, but came that way as stock settings

Windows works in mysterious ways. Or maybe it doesn't work.

Really there's two reasons I could think of:
1. No offense, but maybe you don't remember it correctly.
2. Did you run the windows memory diagnostic immediately or after a restart? I don't know how the tool actually works but if I had to guess it might not move some system stuff in the RAM which might have used those exact 40MB that are producing errors so those never got tested. With twice the RAM available the position of everything moves and the faulty 40MB actually got tested.

If both sticks had passed memtest on their own then it could've been some weird issue with dual channel but as it is I'm convinced it's just one stick that's gone bad.

May I ask which brand/model it is?

Corsair Veangeance 4gb x2
as for specifics. I believe its DDR3 (I am clueless when it comes to specs)
Took a pic of the back hoping this helps
http://imgur.com/a/xE2HC

It's all on the label, thank you.
I pretty much guessed that it was Corsair already, for some reason they have the highest RMA rate. I'm guessing they've been a bit to greedy on the margins just like with PSUs, hope they get back to good quality at a good price, just like recently with the PSUs.

Anyway if you want replace just one stick http://ca.pcpartpicker.com/product/C3h9TW/gskill-memory-f314900cl9s4gbxl
For complete new kit http://ca.pcpartpicker.com/product/2tPfrH/a-data-memory-ax3u1866w4g10dr

Thank you for all the help, Setsul. Your commitment to threads never cease to amaze me.

I will be sure to post an update when I get my new ram (I'll probably just get two sticks cause if corsair is as bad as it seems to be currently. ) Might be a few weeks cause I procrastinate, and I'm living that teenage lifestyle if living minwage part time job paycheck to paycheck due to poor financial choices by purchasing unneeded desires FeelsBadMan