Whenever you download any software, create a restore point in the Windows before proceeding forward. After the complete installation of the software always check for any additional programs that may also get fixed during the installation.
Click on the start icon on the lower left corner of your screen and select control panel from the second tier of the menu. In the control panel, locate the icon 'Add and Remove Programs' and wait for a minute or two for the computer to generate the list.
Click on arrange by date and check whether any other package has been installed on the computer other than the intended software.
Start your internet browser and go to toolbars. Remove any unwanted toolbars and plug-ins installed in the browser without your consent. These tools collect your surfing patterns and send them back to their developers.
Also look for any unwanted search bars installed in the browser without your consent, remove them from the 'Add or Remove Programs' tab under the control panel.
If there have been changes made to your homepage in the browser; spyware is the culprit. It is best to install a Spyware detection tool such as Microsoft Malicious Software removal tool in your computer.
Click on the complete system scan, it will scan your entire hard disk for all forms and versions of spyware. However, it will only locate the presence of spyware. You will need to either remove them manually or install an Antivirus suite to remove these spy softwares from your system.
Image courtesy: 2-spyware.com