Here is what I believe to be the solution.
1.Open you browser to your favorite Yahoo page
2. Click on start
3. Click on run
4. Type regedit (this will open the registry editor)
5. Press ctrl+f
6. In that search window type exactly (no error please) : http:/en.us.acer.yahoo.com/
7. Press okay
8. Once the search has stopped, ensure that you read: http:/en.us.acer.yahoo.com/
9. Press Delete and confirm your choice
10. Close the registry editor
11, Return to your browser
12. Click on tool then on Internet options
13. Click on current page
14. Click on apply.
There it is done
Let me know how if it worked and I am pretty sure it will.