im using directcut 1.22, works flawlessly on XP (tried it on my clone at home, and an HP computer here at work, both running XP) - the buttons look cryptic at first but if you muck about with them you will suddenly click to what they mean, and then the symbols make perfect sense.

for a beginner just wanting to chop a segment out of a large mp3 (ive done it on 300+mb file sizes without problem) dont worry about any of the buttons. other than play and stop. scroll to the beginning of the segment you want to cut... leftclick on the level display to set start position, scroll to the end of the segment, right click to set end position, then just go file->save selection. give it a filename. done