Hi all, I just wanted to give you pointers about this computer heat issues from my own experience. I was given this computer because it wasn't even turning on after being used for two years on a desk. The power supply was fine and wasn't buzzing or overheating. If you are out of warranty and don't mind working on your computer, I suggest you take it apart to clean it. As soon as I opened the case, I removed the motherboard metal shield and lightly retightened the heatsink screws on the CPU and GPU. I then dissasembled the heatsink fan and it clean it with a brush and compressed air (it was really dirty!). I then put everything back together and the computer was able to boot into Windows 7 succesfully. As the OP said with CoreTemp enabled the CPU temps raise under load (obviously). In my cleaned system, the max temp was about 55 and it would idle at around 38-40. Without the shield and without the back case it would idle at around 29 degrees, this indicates that the case is not properly ventilated by design, so to be honest I don't think replacing parts is going to fix the case ventilation design problem.
I made some modifications to the case and now my computer idles at around 25 degrees and it maxes at about 35 under heavy load (full HD video, 3D games). 
I modified the case (you would have to drill a hole with a hole saw, I also drilled some extra holes with a small drill bit, drill in reverse to avoid cracking and snaping the case) and installed a 92 mm PWM fan on top of the CPU/GPU area that I connected to the empty MXM Fan connection (cost me about 10 bucks on ebay, and it's super quiet!). Another thing all of you Inspiron 2205 owners can do is to undervolt the AMD processor with K10STAT to further reduce heat, noise and extend the life of the components. Hope this helps as I believe this computer rules, it just needs a little bit of fresh air!
