You may have a virus. It would be the kind that redirects your internet. If you have a virus your anti-virus software may also be infected or disabled. Use one (or more if you wish) of the links I post to scan your computer. They are free but well tested. You do have to download and/or add permissions to scan. You may have to enter your country. You will have to allow pop-ups for housecall. Spybot is sometimes hard to find the download place just be sure to read the page. You will find it. You do not need to install the trial software. Just select the free versions. Scans can take quite some time. Send a PM if you need more help.
I completely agree-Just had the same problem this week, found 3 trojans from a site that we all have visited from here, but wouldn't completely remove all, so I did a system restore as capoodle mentioned below and now I'm up and running-no problems!!Good Luck! Charlotte :-) The site mentioned has also been fixed and I found it safe today.
You could try a restore to a previous day before this issue. You don't loose your files and this usually corrected the problems I had with Vista