Couple questions that will help me, help you.

1. What kind of internet connection are you on?
2. Do you have any firewalls/anti-viruses installed on your computer, if so, what are they/
3. Are you connected through a router, or are you directly connected to a modem/wall outlet?
4. Do you have installed a spyware/adware scanner such as Ad-aware SE or Spybot Search and Destroy(or others). If so do you regularly run and update them?
After the above questions have been answered, we will have a much easier time trying to help you.
Thanks!

P.S.- I've moved your topic for you, but for future reference please look around at all of the sub-forums and post your thread in the appropriate forum. No biggy, it just helps us organize this place.