The easiest way to check if your computer is infected from Spyware, is to open a web browser (like Microsoft Internet Explorer of Mozilla Firefox) and press the HOME button in the top bar. If you do not see a blank page or see a page other than that of the browser company then your system may be infected. However this test is like touching someone to check for temperature therefore it is always advisable to scan the system periodically for security.
Most of the scanners are free. Systweak Antispyware also offers a free scan for home computers. You can Download Systweak Antispyware for a Free Scan from HERE.