It is possible you may have a infection. I had the same thing happen last year downloading from a site I thought was safe and reputable. It may be worth a trip to the malware forum just to have them check your system out to be sure. At least then we would know if this is something that may not be hardware or software related.
I suggest you go to the Malware Removal and Spyware Removal Forum
and run all the steps located in the START HERE
. These self-help tools will help you clean up 70% of problems on your own.
If you are still having problems after doing the steps, then please post the reguested logs in THAT
If you are unable to run any of the tools then start a new topic in the malware forum and put this in the subject line...I am unable to run any malware tools
If you are still having problems after being given a clean bill of health from the malware expert, then please return to THIS
thread and we will pursue other options to help you solve your current problem(s).Add a link to this topic so that malware tech can see what steps have been taken here