1. Run an antivirus program. Some decent, free ones are: GriSoft AVG, Avira AntiVir.
2. Just uninstall the program. If you have crappy little programs like those for getting weather information, etc, get rid of those. 99% of the time, they are horribly written and are responsible for a large number of problems.
3. Install and run Spybot, Lavasoft Ad-aware and Hijack This. See if you can find any spyware/malware. Obviously, remove it if you can.