dec.bas definition, relationships, removal:

The dec.bas file is an essential part of a particular parasite and therefore is responsible for the pest's malicious activity. Exact purposes of dec.bas depend on the related parasite's type and carried payload. Some threats can use dec.bas to serve annoying pop-up advertisements or store certain configuration settings, while others need it to corrupt files, steal user confidential information or run a spreading routine. In any case, DO NOT open this file!
The dec.bas file is installed and used by Excessive Force.
In some cases a presence of dec.bas does not mean that your system is infected. The file may actually belong to some fully legitimate applications and therefore must stay intact. If you are in doubt, please scan the dec.bas file using you regular spyware remover or antivirus program.