If you're using IE, I suggest to do the following:
- Go to Tools > Internet Properties. Click on Delete Files and Delete Cookies under the General Tab.
- Under the Privacy Tab click on Advanced.
- Click on Override automatic cookie handling.
- Click on Accept under First-party Cookies.
- Click on Block under Third-party Cookies.
- Click on Always allow session cookies. Click OK.
- Click OK under Internet Properties.
- Go to Tools > Pop-up Blocker > Turn On.
- Go to Tools > Pop-up Blocker > Pop-up Blocker Settings.
- Under Filter Level select the High setting.
I assume you have downloaded, updated and scanned using Spybot S&D, Lavasoft AdAware and Microsoft Defender. I would also assume you have updated and scanned with your antivirus program.