Debrick router i tried to update firmware of tplink TD-W8901G model version 3.3 router but mistakely ypdete v6 firmware and brick the router now only show power led green.plz can you suggest me how to debrick(unbrick) it

Sameer, First thing to do is establishing some facts of this router. Please look at the labels at the bottom of the unit and let me know the firmware version. Something like v1, v2 or v4. Pls look here for the example http://www.tp-link.com/lk/Article/?id=46.

You now have to connect the router to a pc with a network cable, that pc is NOT connected to the internet. For instance with a separate laptop, disable the wifi. The network cable connects the router (one of the LAN connections) to the pc.
Invoke a browser and write in the address line 193.168.1.1 with ID admin and password admin. This should open the service program from the router. Go to Firmware upgrade. And follow the rules. Generally you have to check the latest firmware in the TP-Link site and download that file to your pc. IF you have any questions we are always here to help.
Success, Fred

Follow the instructions at http://www.tp-link.com/ca/support/download/?model=TD-W8101G to help in identifying the version of the router and attempt to re-install (correct) software. If unsuccessful the router may have been damaged by the failed firmware upgrade attempt.

Your router is out of support, so it won't be easy to upgrade the firmware.
You should log into the router. With its IP address (192.168.1.1) and standard ID (admin) and password (admin). You get there by opening a browser and typing the ip address in the adress URL line. Please check back to me after you succeeded to get this far. Fred

Reset the device and reconfigure the SSID and Security Key using this procedure:http://www.tp-linkru.com/resources/software/201161016042811.pdf And this: http://www.tp-link.us/products/details/?model=TD-W8901G

I'm an electrical and electronic engineer (Iranian and Persian native speaker) that had the same problem,exactly my modem went to death (just power LED is ON) after upgrading from version 3 to 6 and I have precisely similar TP-LINK TD-8901G ADSL2+ router but I found a great "step by step" tutorial in a Russian website(in their forum) which contributed me significantly;
I hope it might help you too.
[email protected]
+989358817467
http://www.lan23.ru/forum/showthread.php?t=6859&page=1

"it got bricked"? If that means it doesn't work, try to reset to default settings by Pushing and holding for 30 seconds or so,the reset button, usually located on the rear of the device, near the AC power jack, Look for a tiny recessed button, it may be labeled reset.

Try this: http://freedriveronline.blogspot.com/2011/02/tp-link-td-w8901g-td-w8101g.html

1. select the MAC you want to remove
2. change status from Static to Auto
3. click SAVE

even though my pc was set to DMZ port 80 was still in use for the web-interface. I've changed the router web admin port to 81 and now it is fine.

I suggest you use Aobo filter to block website.
http://www.parental-controls-software.net/