It is a dangerous memory resident multipartite virus. It writes itself to the MBR of the hard drive and into the header of EXE files, if there is free space. When an infected file is executed, the virus infects the MBR and returns to the host program. While loading from infected MBR the virus hooks INT 13h and then infects EXE headers that are accessed. On December 27 the virus erases the disk sectors. The virus contains the text string:
SGB:Olga++
