What you are experiencing is typical of smitfraud infections. Smitfraud is responsible for changing the Windows Desktop and using bogus security warnings in an attempt to trick users into purchasing one of several fake antispyware program. SpyFalcon is associated with smitfraud. Sounds like you did not remove all of it or you are reinfected again with SpyFalcon or another variant.
I suggest you read and follow all instructions
in the pinned topic titled Preparation Guide For Use Before Posting A Hijackthis Log.
When you have done that, post a log
in the HijackThis Logs and Analysis Forum
, not here
, for assistance by the HJT Team Experts.
It may take a while to get a response because the HJT Team members are very busy. Please be patient as they are volunteers who will help you out as soon as possible. Once you have made your post please DO NOT make another reply until it has been responded to by a member of the HJT Team. Generally the staff checks the forum for postings that have not been replied as this makes it easier for them to identify those who have not been helped.