OK lets see if I can't guide you through a solution?
First thing I want you to do is close everything that you are not using at the moment. Do you know how to do that? On the bottom right side of your screen, right click with your mouse and choose "exit" or "close" on everything that will allow you to do so.
When you have everything closed, open a new internet browser and copy and paste this in the address bar at the top:
The address bar is the one that has http:// ect at the top of the page when you have the internet launched. You will delete whatever is in the box and then copy and paste the above url in it. Do you know how to copy and paste? You highlight the whole thing by clicking on your mouse button and holding it down while you move your mouse over the top of it until you get to the end and then you either right click on the mouse and choose "copy" while the whole thing is highlighted and then you go to the place where you want to paste it and click one time and then right click and choose "paste".
When you paste the URL above into the address bar, press your enter key on your keyboard. This will take you to the Windows One Care site and allow you to do a free scan to figure out what your computer has that is causing this problem. Go to the bottom of the page and follow the instructions to do a scan. When you are finished with this scan, go to the other two pages listed and complete those scans too.
This should find and repair your problem..
If it does not and you are running Windows XP, go to Start and slide up to programs and then accessories and system tools. Click on System restore and choose a date before you began noticing this problem and follow the prompts to restore it to this place in time.