Was it playing one of them?

当时在播放其中哪首吗
No. Why?

没有怎么了
Well, the media center keeps a history of the last 20 songs played,

媒体中心会记录最近播放的20首歌
but it looks like somebody erased it.

但看来有人删掉了
It wasn't me.

不是我
Ok, I can't tell you who deleted that playback list,

我无法告诉你是谁删掉的记录
but I can tell you exactly when the log was cleared.

但我能查到是什么时候删的
7:43 p.m.

晚上7点43分
Why erase a history of someone else's music?

为什么要删掉别人的音乐播放记录
Because he didn't erase someone else's music.

因为他没有删掉别人的音乐
At 7:36 he loaded an mp-3 via usb drive,

在7点36分他用USB设备加载了一首歌
played it, and promptly deleted it.

播放后就立刻删掉了