I can't help you with the OS issue but I will advise you to get some sort of laptop cooling pad for your computer. I regularly see these at discount sites for less than $20 US. Here is an example...
http://dealmac.com/prices/16807556.html
Radio Shack, Office Depot, even Walmart sells these cool items (pun intended) 
I use sticky backed velcro tape... attach the 4 scratchy loops pieces to the cooling pad corners and the 4 soft loop pieces to the bottom of the laptop. The cooling pad stays in place as if it was part of the computer and it keeps your operating temps down by at least another 5 to 15 degrees Fahrenheit.
The fans run off the power of your USB port and exhaust through the back (usually). I recommend getting the models that include extra USB ports in the cooling pad. Also be careful not to buy the models meant just for desktop use since these ones leave the fans open underneath... which would make it difficult to set the assembly on your bed, the couch, or even your actual lap.
I'm convinced the cooling powers of one of these units is what has kept my G4 operating relatively problem free for 3 years now. I advise anyone who is a laptop owner to get one, no matter what brand of notebook and how cool the manufacturer says the computer will stay.
cheers...
grim