Can someone help me with an audio problem?

So here’s the situation, I’ve had this Windows 2000 professional PC and for the first few days it worked fine but one day my sister used it and it got messed up so I don’t know what might’ve triggered the problem. The problem is that it makes the audio high pitched, it speeds it up a little to make it sound high pitched, any idea as to what I can do to fix this? It’s not the speakers either. Thanks to all in advance for helping or trying to help!