depends as well on what system your running. If it's windows 200/millenium/XP you may be in with a chance PROVIDING you haven't used the computer in the meantime. If you have and have saved stuff, the computer is gonna start 'Over writing' in ares where the mp3's were. thats gonna need a specailist recovery system to get it back and even then your gonna be lucky not to pick up corruptions.
I got a disk with the Tools you can use for this sort of stuff, 650mb's of Specialist tools on one Bootable Cd-ROm. As for using Undelete.exe in dos, I don't think that was supported after windows95 though I have heard of it being possible in 98.
What ever try not to use that section of your hard drive, quaranteen it some how with partition magick or some way other wise over writes are gonna cause you a major headache.
I have heard also in XP that if you do this that you can get it back via system restore some how.. It's something to do with HD configuration or some thing, not sure.
I wish I could give you a copy of those tools but licence prevents it [?
] they could help you out...