Playing iTunes Music Without iTunes

[#1]

I've got all my CDs stored on a network drive, after having copied them using iTunes a while ago. They're in .m4a format and stored with each CD in a separate directory. With hindsight, I shouldn't have copied them using iTunes, but I didn't know any better at the time. I have three music players installed on my PC. Windows Media Player, RealPlayer, and QuickTime Player.
I must be being stupid, but is there any way of playing a whole CD? Windows Media Player won't play the .m4a format. RealPlayer and QuickTime Player will play individual songs, but won't play all the tracks in a directory. I haven't looked into playlists on RealPlayer, but I don't really want to have to create a playlist for each CD.
I'd rather not install iTunes or yet another music player onto my PC. Surely one of my existing media players should be able to do what I want. I'm not asking anything that complicated!
Am I being stupid and missing something obvious?

[#2]

One approach would be to convert the whole lot to .mp3 so they will play in any player.  There is a useful free program called Switch Sound Converter (www.nch.com.au/switch) which should be able to do the job in one batch run. 

[#3]

have you tried Winamp? http://www.winamp.com its free and can play complete directories with one click, also mp4 and m4a

[#4]

Thanks for the suggestions. It looks like I'm going to have to install some more software. I think I'll try the WinAmp option, since it doesn't involve messing around with the files.

[#5]

I had the same trouble a while back when i built a media center PC.
You need to download 2 bits of software.... one so media player can read the m4a file info and a codec so media player can play the file.......
I cant remember where i got the files from, sorry, all i can remember is i found a website explaining how to do it by searching on google.

[#6]

Thanks. I thought that WMP would have used the codecs from RealPlayer or QuickTime Player, but obviously not.
I'll do some searching, but am a bit wary of downloading codecs.

[#7]

K-Lite Codec Pack Pro from Free-Codecs.com sounds like it might do the job.
http://uk.answers.yahoo.com/question/index?qid=20090323062519AAX0frX
I should have done some more searching before asking for people's help.