Regarding video cards, some people like multiple monitors. If you don't need that, you can go with a cheap video card and be just fine. Avoid video cards on the motherboard though. They share RAM and will get in the way of your audio processing.
BTW, which area of India are you from? I'd be curious to know which cities are the music centers.
Guys really help me out
here in india we really have a problm figuring out good pc for Audio production work as mostof them use mac which i cant afford
It use to be that mac was the only really viable alternative for audio. What you're probably missing in India is that over the past 5 to 10 years many composers have switched to the PC platform. And, I'd say most of the members on this forum are exclusively on PC and the mac guys that are on the forum are having to turn to atleast one PC. So no worries about using PC. It's everybit as useful as the mac for music and about 1/2 the cost.
For sequencing and digital audio Cubase and Sonar seem to be the favorites. For hardware I use ECHO Gina on my PC. I use a 7,200 rpm 160gb Western Digital HD. Make sure you get a very, very fast processor as todays sample libraries are CPU and Ram Hungry. I'd use atleast 1.5 to 2gigs of Ram. Get a seperate Video card and as was mentioned get as little audio and video capabilities on your motherboard as this can interfere with your audio and video card as well as hog up ram.
Make the motherboard has fast as possible. At least 400meg front side bus, but I'd go for 800meg. I like AMD chips but others prefer P4 chips or xeon chips. If you're looking toward the future Dual Processors are nice.