I have good news and bad news.
The bad news is the stock cooler has a million tiny screws (Probably 20-25) holding it in place, you will need a small precision philips screwdriver to remove them.
It took me probably 20-30 minutes to disassemble it the first time, some of them are hidden. Once you have it all removed though, most likely the replacement cooler will be easier to install.
It comes apart in s acouple of sub assemblies, you might want to look around online to see if somone has made a step by step guide on how to take it apart..the the new cooler may have instructions.
You can do it, just be patient and take your time, have a large clear table and a few cups to hold all the screws according to there sizes, you will want to bag them up (Seperately) in case you need to send the card in for warranty later down the road.
Chances are, if your card is around 3-6 months old, it's probably like my buddies card, and it's full of dust and hair, and thats why it seems hot and loud compared to new!
After a good cleaning...the temps dropped at least 15c.
That meant tearing it down to get at the insides, if he had just taken a can of air to it every month or so and blown it out, it would never had to be taken apart (Look at the pics and you will see why just blowing it out would not do it)
And thats the good news, you might not need to replace it, just clean it. (If you do that..make sure you are carefull with the white/pink thermal pads on the memory and various places...don't rip them or get dirt on them as they will need to be re-used...try not to remove or disturb them at all!)
You will need a paint brush to remove the dust from the fins (Like 3/4 to 1 inch wide) some canned air and some thermal paste ( I used AS Ceramique) to do what I did, and this may take care of it.
I also suggest adding a 80-120mm fan blowing on the card (The back of the card gets realy hot!) You can add one to the side panel of your case, or do a ghetto mod like I did in this thread:
http://www.appetitefortech.com/forum...ead.php?t=2483
Don't forget you can control the fan speeds from the ATI control panel in the newer driver versions also.
Very plugged up inlet fan!
A couple of pics (Above and below) during disassembly, note all the tiny screw holes...there's alot!) also note how I did not disturb any of the thermal pads...they kind look like sticks of bubble gum, lol
This picture (Above) is why a simple cleaning of the inlet fan (Partially cleaned here) would not fix it...if you look at the fins on the cooler (Wich is hidden under the plastic when fully assembled, and why most people don't realise it's dirty) it is completely blocked off with dust! (It looks black, and came off in one big furry peice)
After cleaning....you can finally see through the cooling fins!!!