THE FLT WAS CRUISING IN VFR CONDS WHEN RADIO CONTACT WAS LOST WITH CENTER. THE PLT DESCENDED & RETURNED TO GNV. HE STATED THAT HE WAS UNABLE TO FULLY EXTEND & LOCK THE GEAR USING NORMAL & EMERG MEANS DUE TO A LOSS OF ELECT POWER. AN APRCH WAS FLOWN FOR THE RWY WITH THE MAIN GEAR DOWN & THE NOSE GEAR IN AN UNDETERMINED POSITION. THE PLT STATED THAT ON SHORT FINAL APRCH, HE SAW THAT HE WAS GOING TO BE SHORT OF THE RWY & ATTEMPTED TO ADD POWER BUT THE ENGINE DID NOT RESPOND. A HARD LANDING WAS MADE ON THE OVERRUN SECTION OF THE RWY WHICH DROVE THE MAIN GEAR INTO THE SPAR CAUSING A PARTIAL COLLAPSE OF THE GEAR & MAJOR DAMAGE TO THE ACFT. THE ALTERNATOR WAS LATER EXAMINED BY MAINT PERSNL WHO REPORTED THE BRUSHES WERE COMPLETELY BURNED OUT. TWO WITNESSES, BOTH OF WHOM ARE CFIS, STATED THAT WHILE ON SHORT FINAL, THEY HEARD TWO POWER APPLICATIONS BEFORE IMPACT BUT THE ACFT HAD DEVELOPED A NOSE HI ATTITUDE & HI SINK RATE WHICH WAS NOT ARRESTED PRIOR TO IMPACT WITH THE GRND. FAA PERSONL LATER TEST RAN THE ENG WHICH CHECKED OUT OK.