WRT4G2 VI wireless router. I was upating the firmware when the power flashed. I have no access to the router's gui and the router is not broadcasting. I am not getting a dhcp address

Unplug the modem network cord from the router, make shure nobody need internet access at the time.

Then access the 192.168.1.1, and it should be the router.
In the Router GUI, change it's address to somethign else.
(192.168.1.X) where X= something between 2 and 254)

Save settings and plug the modem back into the router.

What Brand Router do you have? If you want to reset to factory defaults, behind the router will be a small button a reset button, Push and hold that button for at least 5-10 seconds then let got this will reset the router back to factory defaults... and under the router must be a sticker where the Routers IP address should be indicated to access the GUI/Settings page.

Make sure that by trying to access the routers GUI or setting page that your are connected using Ethernet to be able to access the Routers GUI.

Once in the GUI settings Page check if the wireless radio is turned on to be able to access the router wireless to get connected to the internet.

I hope this helps.

Your wireless router has reset back to default settings. You need to access the GUI of your router to retrieve your wireless info. Connect 1 PC to the router using an ethernet cable. Once you have internet access, open your browser and type in on the address bar 192.168.1.1 to access the GUI. If it doesn't work, try http://www.routerlogin.net. Use "admin" for the username and "password" for the password. Once your logged in, go to the wireless settings and check for the details of your wireless connection.

Reset the router by pressing the reset button for 5 seconds and reconfigure it. The firmware might need to be reset... Then access the router's GUI by typing the default gateway 192.168.1.1

Try to upgrade the firmware of the router. Firmware is the software of the router.
Download the latest firmware of the router. Go to the manufacturer's web site and download the firmware of the router.
Open the set up page of the router and upgrade the firmware of the router. Once you upgrade the firmware of the router, reset the router.
On the router you will find a small reset button, hold it down for 30 seconds. release it. wait for 1 minute. Now unplug the power to the router and plug it back in.
Now you will need to reconfigure the router according to the Internet service provider.

http://www.linksysbycisco.com/US/en/support/WRT54G2/download

Are you able to get to the gui of the router?
If you are able to get inside the routers Gui then that would be a good sign.
Do the following:
1. Go to this site http://www.linksysbycisco.com/US/en/support/WRT54G2/download and select the version. I would suggest you to get the latest.
2. Save it to your desktop. Then extract the file.
3. launch into the router gui
4. Click on Administration then select Upgrade firmware
5. Click on the Browse button and then select desktop then chose the extracted file.
6. Click on the Upgrade button and just follow the on-screen instructions. Normally you just have to select Next.

it may have corrupted firmware, try uploading newest firmware from manufacturer site and upload by wire trough GUI

You can enable the wireless security on the router's GUI.

Access the GUI and look for wireless settings, from there you will see the option to enable the wireless security either WEP or WPA.

Try to reset it, by pressing reset button