For 1 - if your computer is working over 100*C there is possibility that there will be big boom soon :/
How to avoid it - buy new cooler - if this is too slow, or maybe it is broken...
I would suggest you buying 2 new coolers - one for your processor, one - for back of your caser.
There are also programs which you can modify fan speed, but if its allready working on 100%, then you can do nothing with those programs...
I even dont know how to help you here...