sue.t wrote:
Years ago I downloaded what I thought was a pdf file, a manual for something or other. I saved the file to my hard drive and after I clicked on the pdf file to open it, a trojan took over my computer and my security software was shut down.
Thus I learned, even though it appears to be a pdf file, it can be an executable and it can do much damage to your system.
BTW, the security software that didn't detect this intrusion and let itself be shut down was Microsoft Security Essentials.
Years ago, this was a security hole with Adobe Reader, a patch was issued. You should be using Adobe Reader 9.0 or higher, make sure you have all the security updates..
As far as the OPs issue, I would say that they have malware that most likely has a virus payload to boot.
The usual fixes apply here, run malwarebytes, Ad-Aware, and antivirus.