Is there a way to switch off Sub-Woofer, as I don't require bass while working with audio, where my work involves only vocals ( I mean conversations). Do I need to install any supporting Hardware/Software additionally. Please help me out of this
Your sound card should have come with a disk with the drivers and utilities. Go to the control panel and see if there is a creative or soundblaster program there. If not just go under sounds. You should be able to switch between 2.1 speakers to stereo (2 speakers). When you need the bass back, switch it back to 2.1 speakers.
Pretty much all 2.1 speakers connect though the sub to the PC, then to the satellite speakers. Many of them have an option to turn down the bass level though, check your speakers for that. Or you can use a graphic equalizer and turn down the lower frequencies.
No clue why having lower frequencies would cause you any issues, if the vocals do not have the range to hit the crossover to the sub, it won't get used. It's like wanting to take out your rear view mirrors till you want to see behind you in the car, then climbing out and installing them again.