NDISRD.sys is a malicious parasite component responsible for implementing main parasite functions, hiding its running processes or delivering a destructive payload. The NDISRD.sys file usually works in the same manner as a system service or a device driver. In some cases it contains essential settings of a particular parasite.
The NDISRD.sys file is installed and used by Alpha Antivirus.
In some cases a presence of NDISRD.sys 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 NDISRD.sys file using you regular spyware remover or antivirus program.