Hi,
Perform the steps mentioned below and check if it helps:
Method 1:
What is browser hijacking?**http://www.microsoft.com/security/pc-security/browser-hijacking.aspx**
Note: The Reset Internet Explorer Settings feature might reset security settings or privacy settings that you added to the list of Trusted Sites. The Reset Internet Explorer Settings feature might also reset parental control settings.
We recommend that you note these sites before you use the Reset Internet Explorer Settings feature.
Method 2:
How do I remove a computer virus?
http://windows.microsoft.com/en-US/windows7/how-do-I-remove-a-computer-virus
Note: The Microsoft Safety Scanner expires 10 days after being downloaded. To rerun a scan with the latest anti-malware definitions, download and run the Microsoft Safety Scanner again.
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Method 3:
You can also try resetting the host files and check if it fixes the issue.
How can I reset the Hosts file back to the default?
**http://support.microsoft.com/kb/972034******
Hope this information is useful.