i have windows vista and limewire 4.18.8.since a few days my music downloads will becompleted to 100% but none of them i can listen to i even did take limewire completly of the pc and reinstalled it.

Which player are you using? If you're using LW's player, disable that (tools > options > player) & see whether songs will play when you use a different player.

Is it only songs that you've recently downloaded that won't play, or do songs that you downloaded ages ago have the same problem?

If it's only songs that you've recently downloaded, maybe you downloaded some junk. Check out this link for more info: Files I download won't play