Help with sound pls

Is this a case of sounds from other programs interrupting other sounds, or just loss of sound all together? Oftentimes skype's sounds causes trouble for other programs, if you have skype open I would suggest disabling the audio for all of the notifications. And I don't claim to be an expert on PC audio, but getting a new sound card might help, they aren't that expensive.

headphones or soundsystem?

There are lots of internal soundcards that might do the trick, as well as some external usb ones that might be cheaper and help as well.