This is an Excel macro virus. It contains two modules COP and ROBO. Module ROBO contains the auto-routine Auto_Open that is executed on opening an infected file. That macro infects the PERSONAL.XLS file and assigns virus code as being executed on activating a sheet (SheetActivate handler). As a result, the virus will infect current files (books) on activating a sheet.
On March 1st the virus inserts the texts into current sheet:
ROBOCOP Nightmare Joker [SLAM]