please help me homebuilt a Assembled Desktop PC 20000Rs (350 to 400 $)

I can't vouch for prices and availability in Mumbai, but here's a nice idea of where to start.

PCPartPicker part list

CPU: Intel Core i3-4330 3.5GHz Dual-Core Processor ($114.99 @ NCIX US)
Motherboard: ASRock H87 Pro4 ATX LGA1150 Motherboard ($89.98 @ SuperBiiz)
Memory: Team Vulcan 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Newegg)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($48.98 @ Newegg)
Optical Drive: Asus DRW-24F1ST DVD/CD Writer ($20.99 @ Amazon)
Total: $374.92

If you want low power consumption, Intel is the way to go. Their integrated graphics aren't as good an AMD's, but it's more than enough for heavy web surfing and office productivity. This power supply will be enough for any mainstream GPU, up to a single 6-pin PCIe connector.


PCPartPicker part list

CPU: AMD A8-6500 3.5GHz Quad-Core Processor ($104.24 @ Amazon)
CPU Cooler: Cooler Master Hyper TX3 54.8 CFM Sleeve Bearing CPU Cooler ($19.98 @ NCIX US)
Motherboard: ASRock FM2A88M EXTREME4+ Micro ATX FM2+ Motherboard ($92.55 @ Newegg)
Memory: Team Vulcan 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Newegg)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($48.98 @ Newegg)
Optical Drive: Asus DRW-24F1ST DVD/CD Writer ($20.99 @ Amazon)
Total: $386.72

Here's an alternative AMD build. It will eat a little more power, but the integrated graphics means you can do some light gaming without a discrete GPU.

A side note on both builds, A 640GB or 750GB HDD is only a couple dollars more than your requested 500GB.

Can you list a few online sellers you will be using so I can see their prices? I have no idea how much to cut the components without know the international markup on them.

To be honest bro, if you want gaming build, there would be nothing at 20,000. I too live in India. Hardware here is more expensive than outside India.
For a good, future proof build, I would advise you to extend your budget to 30,000.

With this build, you could do slight gaming at medium-high settings, with games like fifa 13, crysis 3 etc.
For motherboard, go with the MSI FM2 A75MA E35. 4500RS.
Ram, RipjawsX 2x4GB 2133mhz: 6800RS
You can get any 8gb but it must be 2133mhz like this
http://www.flipkart.com/g-skill-ripjawsx-ddr3-8-gb-2-x-4-gb-pc-ram-f3-17000cl11d-8gbxl/p/itmd2rysxxtuvfhy?pid=RAMD2RYREMKEFFSR&otracker=from-search&srno=t_1&query=2x4gb+ram&ref=3f515315-2d71-4ef9-b414-87147bd110b4

For processor , has a good integrated graphic card too, AMD A10 5800K. 9,000RS.
This can play games like Battlefield 3, FIfa 13 without a graphic card as it has a good graphic card already inside it

Power Supply, Go with the VS 450 for 2000.

For hard drive, WD caviar Blue for 500GB. 3500.

For Optical Drive, I would recommend any one which is 1000.
All adds up to 24000. Its more then the RedJaron's build but you can do slight gaming with it and it will run those games like GTA IV,Hitman Absolution etc.
I would recommend you the CX 430 Power supply which is 1000RS more but its totally worth it. It has sleeved cables and its bronze certified. I would Highly recommend you to buy it.

Hope that helped.
Hope that helped.

Ok go with the same parts,but make changes in the motherboard and processor.
For processor, go with the FX 6300 for 8000. And motherboard, MSI 970A G43 5500.
As it has Crossfire capability which can handle 2 graphic cards.Save money for now and buy r9 270x in future.

There's no way to connect it. Do you have a VGA slot on your TV? If yes,It can be done.If no,you have to get this mobo
http://www.flipkart.com/gigabyte-ga-78lmt-usb3-motherboard/p/itmdegddysfvzuqm?pid=MBDDEG8JWXZJAP4F&otracker=from-search&srno=t_3&query=am3&ref=ae0dbd92-96ec-4b32-b3f7-474740d95c21

but its not a future proof board as it has no crossfire support.
I would recommend you the MSI 970A G43(the previous one)
and get this cheap ass graphic card temporarily which will help you to connect your pc to your tv

http://www.flipkart.com/zotac-nvidia-synergy-210-tc1g-ddr3-512-mb-graphics-card/p/itmdpxrfhvczwmtz?pid=GRCDPXQRGVFXCDKU&otracker=from-search&srno=t_8&query=at+graphic+card&ref=5acf7d9f-10e4-4a9b-9d1c-ad4139b12493

First, Miit, I don't think you're doing any favors here. It's like you didn't bother reading his initial request outside of his budget. Jiten has specifically asked for low power consumption and web use first. Gaming is NOT a priority right now. So why are you recommending overclocking an AMD, which not only raises power consumption, but also requires more expensive cooling parts? He's already said he'll be adding a discrete card later up to ₹8000. I'll be shocked if the 270X you mentioned will ever go below ₹16,000 in the next two years. Why would you recommend an nVidia 210, a card that's arguably weaker than the integrated graphics in an Intel i3? And you need to check your parts better before recommending someone a CPU and mboard that has no video output.

Jiten, you're simply not going to get a "future-proof" system for ₹30,000. The budget is basically limiting you to parts that are already at least one year old. If the parts are already significantly dated, then future-proofing is simply impossible. However, that doesn't mean you can't get a very capable system for your intended use ( lots of web use and light gaming ) that will last a few years at the very least.

I strongly recommend you stick with the i3-3000 right now. The FX-4300 is a little stronger than the i3 in heavy computing tasks, but you won't be running into any of that web surfing. The FX also has no graphics of its own so you'd have to buy an add-in card or get a motherboard that has integrated video. The A8-5600K is also around the same price of the i3, but it isn't as strong a processor. The trade-off is you will get slightly better graphics to enable some mild gaming from the start rather than waiting a year. With all that considered, I say get the fastest i3-3000 series chip you can afford.

Next, running multiple graphics cards is not a requirement. While a lot of people talk about multi-GPU setups, it's actually much more common to run a single powerful GPU. You said you plan to add a GPU next year. When planning GPU upgrades, you need to make sure your PSU can power it, mainly that the PSU has the proper PCIe power cables to power the card. Most cards in your listed price range either don't need an auxiliary power cable or only need a single 6-pin cable. In your case I'd recommend getting a PSU that has a 6-pin connector, just in case you're able to get a good deal on a stronger GPU. If you can find a PSU that has two 6-pin cables for a similar price, all the better. However I think a second GPU for you is unlikely. By the time you need to upgrade your graphics, chances are you can get a single better card for close to the same money as buying a second card.