You can use the sound recorder that comes with windows, to do some basic editing to sounds. Eventually, I'd recommend a shareware sound editor like Goldwave for more sophisticated (yet still very basic) editing. The important thing is that the sounds are in the right .wav-format. They should be 8bit mono, 22050 mhz.
The easiest thing is to load in the original sound in the sound recorder, then cut out the sound, and copy-paste in the new sound, and save under the original name. Then you will automatically get the right format.