can't delete trojan horse virus

From: thomas (thomas_at_discussions.microsoft.com)
Date: 06/30/04 

Date: Wed, 30 Jun 2004 01:01:01 -0700

 -i seem to have been infected by a trojan horse virus, as listed by my a.v.g. anti-virus soft-ware, and it is only one file; the soft-ware was unable to delete/remove it, unofrtunately. but my computer will not allow me to manually delete the file either; the file is an "...Application Data\RNCR.EXE file. what can i do? the virus is less than one day old.