Typically, denoisers are the kind of software that makes you want a faster CPU. The fan will run a lot on a laptop.
I have not found a good, free (or open source) de-noiser, even though Audacity has some noise removal capability. There are several good shareware programs though.
Notes:
The free version is useable but is limited in ripping speed and won't let you burn a CD. A few other features are also disabled. However, the registration is inexpensive and well worth paying for in speed and features.
It has replaced a number of distinct players on my computer. I use it to play all audio files and most video files (.avi, DVDs and such.) It works very well except for some problems playing wmv files.
The best of all, it loads and starts playing VERY fast.