Graphics card (probably) dying, need help

I am not really that skilled in PC building, but I know the basics.

Lately my computer has been very loud, the fan is going nuts. We are talking about 5-6 years old PC, but I am mostly watching video on it these past couple of years. I have a cat so I open the case every couple of months to clean the insides with a vacuum cleaner but honestly there is never too much junk inside (or I would do it more often). For some time now the fan is going to higher and higher levels and I don't know why, it's perfectly clean inside. I presume it must be the graphics card, because it mostly happens when I play video(?). It just spins up, stays there for a bit, spins down and on and on like that. I have been using an utility named Core Temp which monitors my processor cores temp. and there is no problem there - it's steady at around 70 degrees Celsius.

I could be wrong at any of my presumptions so that's why I ask for help - what can I do to determine the cause of the problem and resolve it? Or is the PC just too old and cranky and I should just accept that and move on? Any advice would be gratly appriciated!

It's possibly failing, but I'd suggest getting the AMD tool (I forget the name) to monitor your GPU temp if you can't see it easily, and see what the temp gets to and GPU usage is when you're having the loud fans issue. You could also try underclocking the card slightly to get more life out of it, if it is indeed the card temp causing the fan loudness. I haven't used a monitoring tool with an AMD card in a while so I forget which software allows what, but it shouldn't be hard to find - you could try this first:

http://support.amd.com/en-us/kb-articles/Pages/AMDSystemMonitor.aspx

You may also have a bad fan somewhere in the case, or on the CPU, etc - did you check each to determine it WASN'T just a replaceable fan in the case somewhere?

Yeah find a program to monitor all your system temps including your graphics card. Are you actually having issues besides fan speed? Games stuttering, ctds, bsod etc?

"I have been using an utility named Core Temp which monitors my processor cores temp. and there is no problem there - it's steady at around 70 degrees Celsius."
I'm going to assume you meant your video card is running at 70 celsius? Cuz that's way too hot for a CPU.
It sounds GPU related but try running some games with your case door open and narrow down which fan is actually making the noise, that'd be a good start.
I use a vacuum attachment for the outside of my case (never the inside, ESD) but you really need an air duster to blow out any dust stuck inside the heatsinks of the CPU and GPU.

Naw, those phenom's run that hot normally. They shouldn't idle there though

Thanks everyone for suggestions, I downloaded the tool which monitors both CPU and GPU load and it looks like it's actually CPU related - the fan kicks in every time my CPU hits 40% or more. The GPU stays at minimum values all the time.

Also, as I was watching this tool - and this will sound very dumb, but here we go - I realised the usage CPU spikes when I have Cookie Clicker on screen, which is consistent with the time the problems started. I have been having that opened in Chrome window (1/4 of the screen) while watching some videos, mostly GB content on the rest of the TV (PC have been connected to my TV only for years now). Also going to Cookie Clicker options and dropping the graphics down drops the CPU load considerably.

So now the question is what can I do? I will open the case during the weekend and make sure it's clean. The processor is not a high end or anything, but surely it should handle a browser game and VLC/youtube player, right?

And yes, I have been using compressed air can to blow out everything when opening the case, I just forgot to mention that.

Even with the compressed air, your fans will get gummed up with dust on the axles. Especially in a 5-6 year old machine. Just buy a new fan. They're pretty cheap. Your CPU might also need some new thermal paste in a machine that old.

@oursin_360: Yea I know AMD typically run hotter (been a long time since I've had one or read about their temps) but my initial reaction (without thinking about load) was that it just sounded c-c-c-crazy hot!