some computer tech questions

[Willdue]

I have a few questions, maybe someone can help...


I juss bought a "my book" external hard drive, and I saved all my songs from my old pc, and triying to get them on my new pc. They load but won't play, it says there mp4? Is there anyway to convert them to mp3?

Also, my netzer program got "corrupted", so I deleted all the files, but it only deletes all of them but 2 of the files in the folder, it says I "need permmision" to do it? And now when I try re installing it, it says that it can't cause its open and running. It says its running in the taskbar, but its not there.

Another, my old pc, I gave it to my gf's brother, its not detecting the modem, but its in and in correctly?