Speakers volume control

boston speakers that came with gateway computer volume control on speaker does not work all the time you have to play with it so the other speakers will catch had to give computer back to gateway after buying to put a sound card in also have crackling sometimes had problem for years thinking about upgrading speakers do I need to upgrade sound card memory card and or mother board if I upgrade
ior should I get speakers fixes or can you help me in a different way

thanks
darrell