I would convert stuff to mp3 files. It is the most universal Music Format, for Computers at least. Plenty of music converters on the internet. I like "easy cd-da converter", but many more to pick from.
The Music will sound no better then the source quality, but if you converted to a mp3 @ 320 bit rate then you will probably at least sound as good as original. unless the original files are one of the lossless formats.
If your Music files are Copy protected, Windows Media Files, then it is may be more complicated, for that reason I always avoided the format, and have not spent much time messing around with converting them.
I did once burn Copy protected wma files as a regular Music CD for a friend, then reripped the music back to the computer as mp3's from the CD, but that would be time consuming if you had a lot of them.