What it does:
Trojans attempt to gain information from your computer by disguising as a trusted program. Spyware attempts to gather information about you and your browsing habits in order to send you targeted ads via spam email. Both are often hidden inside other programs (e.g., screen savers, time and date updaters, weather updaters) and infect your computer when the program runs.
How to protect yourself:
Avoid these by being aware of what you install on or download to your computer. If you are unsure of its legitimacy, search for reliable information regarding the program before adding it to your system. Updated anti-virus and spyware detection programs also are helpful in protecting your computer.
If you think you’ve been infected, update all virus definitions and run a full scan with your anti-virus software. If your system still appears compromised, fix it and change your password again. Also, check your online accounts (email, bank accounts) and change those passwords in case they have been compromised.