What is the make and model of the computer, how much RAM (memory) does it have, and what operating system does it use (Windows 7, Windows Vista, Windows XP, etc.)?
Does this problem only occur when playing music directly from the internet, or does it also occur when playing files from a cd or files that are stored on a hard drive? If the latter, on what drive are the music files stored (on your internal "c" drive that also contains Windows and program files; on a second internal hard drive; on an external hard drive)? If they are stored on an external hard drive, how is it connected to the computer (usb, firewire, esata)?
What program are you using to play the music files?
What kind of internet connection do you have (cable, dsl, dial-up)? Go
here and test the download and upload speeds of your connection, choosing the closest location from among those offered. Let us know the results.
Regards,
-- Al