if you're mining Litecoins, you should use GUIMiner and your GPU (should have 2 options, 0-0 and 0-1 "cpu name" 0-0 is your GPU), try different intensities.

intensity 0 means off, it wont mine.
intensity 20 is dangerous, hope you're living in the poles or have a fire extinguisher nearby.

personally, i have an AMD 6870, i leave my computer mining at Intensity 14 all day and manually set the fans to work at 90% and the temperature never exceeds 80 Celsius (GPU fans are programmed to never work at high % unless your card is already burning when you set it on auto, this is a trick they use to make you purchase new cards).

the only downside here is the noise, high % fans, higher noise.