I'm sorry to hear that my Name is*****'d be glad to assist with this matter....
May I ask which operating system are you currently using?
To fix this error, you can check and remove your publisher from Untrusted Publisher list in Internet Options if any. Follow these steps to know how to unblock a software, publisher.
1. Open Internet Option. You can access Internet Option either from Settings or Internet Explorer Settings.
To access Internet Option from Settings, go to All Settings by clicking on Start and selecting Settings. Open Network and Internet from the options. Under Network and Internet, click on WiFi tab or Dial-up tab, and then click on Internet Options under Related Settings section.
To open Internet Options from Internet Explorer, click on Tool button and then click Internet Options.
2.Once the Internet Options window pop-up, go the to Content tab and click Publisher button.
3. From Certificates window, click on Untrusted Publishers tab.
4. Here you should see your software publisher listed. If it is listed, click on it once and then click on Remove button to unblock the publisher from untrusted publisher list.
Now try to run the software, which was giving security warning and see if the error has been resolved.
Please provide D-Link Modem Model number...
In the link provided is a link that assists in troubleshooting matters such as yours. I do apologize for the delay and would like to continue to assist until this matter is resolved.....
I hope this helps solve your issue...
For my own understanding, I read that the second router connected you to the internet. Is there need of more assistance until resolved? Or problem resolved?