I have a sound card creative sbo 100. but i have not drivers for it sumanasiri

If your computer came with a motherboard disc the sound drivers could be on it
click start control panel administrive tools computer management device manager sound video and game controllers could be a yellow question mark? right click to re-install drivers
cnetdowload.com if these drivers are not suitable on the home page you should see the download software finder under that there will be a list platform, category sub category price from the category drop down list select drivers then from the price drop down list select free or which ever applies to your need
http://download.cnet.com/Realtek-AC-97-Driver-Windows-98-Me-2000-XP-2003/3000-2120_4-10238712.html
Realtek AC