Why am i not able to upload songs on my mp3 player?

i use windows xp on my computer, and recently i haven't been able to get songs on mp3. The computer detects the presence of mp3 player and even shows a window asking whether i want to sync files into it but when i click OK it takes ages to find the "device" and when i try using copy-paste and go to my computer, it shows that it is searching for files. But as soon as the player is removed everything goes back to normal.