Thanks for confirming!
The window you see is something like a virus. Your web browser contains infected component that displays such warning screen. It is not dangerous, but it may prevent you from opening certain, if not all, web pages.
The owners of the number you see are scammers who, if you call them, will ask you to access your computer remotely to "fix" the problem. All they do is to manually remove the warning screen which they designed in the first place, and for that "service", they will charge you a great deal of money - usually something about $200. They can then put another similar virus which can cause the same problem in the near future, just so that you can call them again (and pay again!). They could also steal your personal documents and what not.
So, you did a good move by hanging up on them. If they call you back, you can tell them that you now know who they really are, and if they call again, you will report them to the police.
As far as removing that virus (warning window) goes, there are several ways. I will provide the instructions for you to follow:
1. First, click on this link below to download a free program called AdwCleanerhttp://tinyurl.com/lk49358
You can use to remove the infected browser component which will remove the warning screen you see. In case it doesn't allow you to download the file on the infected computer, you will need to use another web browser or another computer where you can download the file and run it on the infected computer. If using another computer, you need to transfer it to the infected computer. You can do that using a removable flash or hard disk drive, or any other way.
3. Once downloaded, start the program. Make sure to exit all running programs first, especially all web browser windows. Once the program has been started, click Scan
. Wait until the scan has finished and then click Cleaning
to remove all found infected and unwanted files. This program is safe to use because it only scans for programs and components included on its list so it won't remove any personal data or programs that you actually use.
4. Once that is done, it will require you to restart the computer, so do it. After the restart, all browser add-ons and modified settings should be gone, including that bogus window warning.
Let me know if this helped.
If you require further assistance, let me know.