first ensure that the computer is free from infections:
Download, install, update and do full scan with these free malware detection programs:
Malwarebytes (MBAM): http://www.malwarebytes.org/products/malwarebytes_free
SUPERAntiSpyware: (SAS): http://www.superantispyware.com/
then follow the advice from S. Stanley , clean up your computer, in this post:
third: tell us about your system:
make, model and model number of pc
current antivirus
OS and service pack
is windows search 4 installed