The sounds are in the .pk3 files in the /base folder. .pk3 files are simply .zip files renamed; rename the assets*.pk3 files to assets*.zip and you should be able to open them and find what you need.
XP has a built-in zip viewer, so getting in shouldn't be troublesome; if so, you could use utilities such as quickzip, pkzip, winzip, etc.
I'm not sure which .pk3 file the sound effects are in (they're mp3/wavs as I recall), but it shouldn't be too hard to find them - there's only a few .pk3s in the /base folder.
"Words are deeds." - Wittgenstein