Hark is a simple Word Macro virus. Infected documents have macros called "AutoOpen" and "Harkone".
This virus has an interesting activation routine. On 1st of June the virus maximizes all active windows, changes the font size to 60 and insert the test "HARKONE" and "NJ [SLAM]".
SLAM is a name of a virus-writing group.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Technical Details: Katrin Tocheva, F-Secure