ok, if you dont have it, download cpu-z
here . then open it, and see what the codename is. it could be winchester, venice, or new cassle. tell me which it is. if you have a venice, flash to bios 1011. if you have something else, flash to 1009. you can get the bios file
here get either 1009 FINAL or 1011.007 BETA.
on your mobo cd, there is a program called Asus Update. install it. use the program to update the bios from file. select the bios file on the computer that you downloaded. it will run, and then you will have to restart. enter the bios and configure your settings.
also, 45C isnt too hot, you can get it up to maybe, 55C before you start to worry. but try to keep it below that at all times.
remember to follow the guide. do it exactly, because it works really well, and you can really see what you computer can do. good luck!