When ever you get "strangeness" like that I'd recommend a good virus scan. Even if you are running Antivirus software they canslip through. Just because you eat your veggies doesn't mean you cant get a cold. I happen to like Vipre, but you can download Maleware Bytes or SuperAntiSpywareREmover (yes, it is a real product). I like Vipre mostly because it is updated daily and it really doesn't ask any questions, It just goes ahead and cleans. Start it before you go to bed or before you head out on the trails to go wheelin - thenit doesn't take any of your time.
If you ever need to do a virus scan,
1. google / download Vipre Rescue,
2. reboot your PC,
3. press F8 right before Windows starts to load,
4. choose "Safe Mode"'
5. run the Vipre Rescue file that you just downloaded
6. Let it clean anything it finds.
If anyone has any questions, let me know and I will help. I own an IT consulting company and viruses piss me off as much as the person that gets them.