Help please.
I have a 2820Vn which has worked reliably for the last 3 years. Today, in order to get the undivided attention of my teenagers, I turned it off and guess what - it won't restart.
I have either, a rapidly flashing DSL light, or all of the lights flashing rapidly.
I have tried a factory reset - but this doesn't seem to make any difference, and I can't open the router from my computer using either the original IP address or the default setting.

At present I have resorted to my old router and modem - but its definitely not ideal.

Ideas please?

If is not coming on something must corrupted and you may need to reflash the firmware with the utility tool from here (V3.6.5 for windows)
http://www.draytek.com/index.php?option=com_jumi&view=application&fileid=17&Itemid=586&lang=en

Get the firmware 3.3.5.2 from here
ftp://ftp.draytek.com/Vigor2820/Firmware/V3.3.5.2/AnnexA/
... use modem code 2471201 or 232201 ... but is important to use the *RST* file to clean everything
(this is the safest way but you will need to set everything back from the begin)

follow this order to avoid time outs (have the upgrade tool ready and stand by first)

Master reset the modem (you did)
Switch Off the modem

-use ethernet cable & not via wifi
-Disable temporary firewall at pc

-open the utility upgrade tool 3.6.5 and connect ethernet cable to modem
-Type the IP address 192.168.1.1 but make sure the pc is at the same ip range
-load the *RST* file
-password try admin or leave it blank next time you get time out or error message
- let the upgrade tool open & stand by ...

While the modem is already turned off ... press and hold gently the small reset hall button ... Switch On the modem while the reset button is still under gently press ... and while the leds flashing ... let go the small reset button ... and press the send button at the upgrade tool before the leds at modem stops flashing fast

Do not turn off modem till process finish

Now you can load safely via the utility tool or via the web UI the latest firmware 3.3.7.4 from below ... use modem code 2471201 or 232201 ... again with the *RST* file to clean everything
ftp://ftp.draytek.com/Vigor2820/Firmware/v3.3.7.4/Annex%20A/

If any questions come back because any mistake can cause more trouble