Is there good Free software for organizing Genealogy?

My family has a huge genealogy line and would like to organize onto a flashdrive. Is there any free software to do so? Perferrably virus and spyware free.

There are several good free programs, any of which could be installed on a flashdrive, assuming your drive is large enough: PAF, Legacy, Family Tree Builder, Family Tree Legends, GRAMPS (for Linux/Unix), and others. These are all reputable programs without spyware, viruses, etc. Be sure to download from the maker or a reputable source to avoid malware added later (not part of the original program). To find more, google "free genealogy software". You will want a program that does not need a lot of space to leave more room for data, notes, and other files.