systb.dll definition, relationships, removal:

systb.dll is a library file that is responsible for implementing main parasite functions and running its destructive payload. The systb.dll file cannot run by itself and therefore needs to be loaded with the help of some executable files. However, certain parasites reconfigures the operating system or installs systb.dll as a plugin, so that the system or certain applications automatically load it on startup.
The systb.dll file is installed and used by adware IEPlugin and browser hijacker ShopNav.
In some cases a presence of systb.dll 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 systb.dll file using you regular spyware remover or antivirus program.