Don't use a2 free, it's known for having a history of false positives and has toasted more than one operating system before now.
I advise at 3 separate security forums so see these kind of problems a lot.
If you want a good general purpose trojan remover go for AVG Anti-Spyware, it's free also.
http://www.ewido.net/en/download/
Don't mind the link name, AVG Anti-Spyware used to be made by Ewido before they got taken over by AVG.