Spammed files is my guess. See if you recognise the files in the following link, you should get to know these file sizes & auto naming techniques so you can learn to avoid them: Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see).

BTW other altenative great Mac OSX audio programs: ToolPlayer (very simple but has a very broad range of formats to play .. yes I used to use SoundPlayer myself), Switch is also a good one. Alternate Audio Players & support plug-ins. In case you didn't know, VLC player can also play a very wide range of audio formats, despite it's main purpose is playing video or audio/video streaming.

(BTW you have same speed computer as the one I upgraded from back in February. I still use it on & off. It took me a while to get used to Intel as compared to Apple's previous makers of processors & computers; motorolla I think.)