I am afraid it sounds like you have downloaded a form of computer virus called "malware". A short term for malicious software. It is software that is usually visible to you which runs to cause you problems. This is opposed to viruses that try to run without being noticed.

The download you accepted was likely something recorded here on Mahalo as Scareware: http://www.mahalo.com/scareware. In short, it tries to scare you into downloading by tricking you into thinking you may be getting a virus or something.

Now, you need to get rid of this malware. It seems to be new, and I did not turn up many results on google, but there is a group called the Geek Police that seem to have a reasonable solution. Although, you might want to use your own antuvirus as opposed to theirs. That decision is up to you.

Geek Police's Information Sheet: http://www.geekpolice.net/malware-urls-f41/malwareurlirblockcom-information-t14078.htm

Geek Police's Removal Process: http://www.geekpolice.net/malware-removal-guides-f12/how-to-remove-personal-antivirus-delete-guide-t7526.htm

My last piece of advice: get any critical information you need from the internet (virus removal directions, anti-virus updates, additional antivirus tools). Then disconnect your computer from the internet until you resolve this issue. I suggest this because if this malware is trying to steal your personal information, it will be attempting to upload it to a thief's server. If you are not connected to the internet, then the virus cannot upload stolen data.

Best wishes.