Hello,
I'm sorry you are having issues with your device.
If just the Power light is flashing it is not a good sign but there are still a few things you can do to see if it is broken and needs to be replaced or if it just lost its configuration.
From the quick start up guide:
http://www.cisco.com/c/dam/en/us/td/docs/wireless/access_point/csbap/wap121/quick_start/guide/WAP_121_321_QSG.pdf
Flashing power light means it is booting up or it is performing a firmware upgrade, in any case it shouldn't take more than a few minutes to go back to solid.
This is what i would recommend for you to do:
1- Check that you are using the right power source. Are you suing a PoE switch? What kind? What about a power adapter? Do you have one? Did it come with the unit? Do you have a spare 12V 1AM power adapter that you can use to see if the issue is the adapter?
2- Assuming you do have a power adapter, connect the WAP directly to your PC, make sure it is powered on and hold the rest button for 35 seconds so the device will reset.
3- On your PC, configure a static IP address on the ethernet adapter and assigned 192.168.1.100 to it with subnet 255.255.255.0
4- Try to access the web GUI of the WAP going to http://192.168.1.245
If you are successful then the device is OK and you just need to reconfigure it, if it doesn't work then I would recommend to contact the Small Business Support center at 866-606-1866 and create a case.
Please let us know if you have any more questions.
