Short video on how to replace a hsf. If your machine is running hot, you should use compressed air (when the laptop is off) to blow out the air ducts. You can use this video to take apart your machine and apply better thermal paste to lower temperatures.
Here are a few good thermal pastes:
http://rcm.amazon.com/e/cm?lt1=_blank&bc1=000000&IS2=1&bg1=FFFFFF&fc1=000000&lc1=0000FF&t=mr342chan-20&o=1&p=8&l=as4&m=amazon&f=ifr&ref=ss_til&asins=B0002VFXFE
http://rcm.amazon.com/e/cm?lt1=_blank&bc1=000000&IS2=1&bg1=FFFFFF&fc1=000000&lc1=0000FF&t=mr342chan-20&o=1&p=8&l=as4&m=amazon&f=ifr&ref=ss_til&asins=B000FZ1YSW
http://rcm.amazon.com/e/cm?lt1=_blank&bc1=000000&IS2=1&bg1=FFFFFF&fc1=000000&lc1=0000FF&t=mr342chan-20&o=1&p=8&l=as4&m=amazon&f=ifr&ref=ss_til&asins=B002CQU14A
Thermal paste comparison guide-
http://benchmarkreviews.com/index.php?option=com_content&task=view&id=150&Itemid=62
Here is what thermal pads I would buy if you want to replace the northbridge thermal pad (it is a sheet, you cut what you need)-
http://rcm.amazon.com/e/cm?lt1=_blank&bc1=000000&IS2=1&bg1=FFFFFF&fc1=000000&lc1=0000FF&t=mr342chan-20&o=1&p=8&l=as4&m=amazon&f=ifr&ref=ss_til&asins=B008X0UKV8
Here are some fan choices-
http://www.amazon.com/s/?_encoding=UTF8&camp=1789&creative=390957&field-keywords=t61%20replacement%20fan&linkCode=ur2&tag=mr342chan-20&url=search-alias%3Daps&linkId=A34XH6FWLHLPP5PF