BEFORE TAKEOFF, THE NON-INSTRUMENT RATED PLT WAS ADVISED THAT VFR FLT WAS NOT RECOMMENDED. WHILE EN ROUTE AT 9500 FT, THE PLT RPRTD HE HAD ENCOUNTERED HVY RAIN & HE REQUESTED VECTORS AROUND THE STORM. THE ATC CONTROLLER (CTLR) REPLIED THAT HE COULD NOT PROVIDE WX INFO DUE TO THE LIMITATIONS OF THE ATC RADAR. SUBSEQUENTLY, THE PLT RPRTD '(WE'RE) IN TROUBLE. WE'RE COMING THROUGH SOME VERY HEAVY THUNDER.' THE CTLR SUGGESTED THE PLT TURN RIGHT TO 180 DEG TO REVERSE COURSE. THE PLT ACKNOWLEDGED THAT HE WAS 'TURNING RIGHT 180 . . .' THERE WAS NO FURTHER RADIO CONTACT WITH THE ACFT. SUBSEQUENTLY, AN IN-FLT BREAKUP OF THE ACFT OCCURRED & WRECKAGE WAS SCATTERED OVER AN AREA OF ABOUT 1 MILE. WITNESSES NEAR THE ACDNT SITE RPRTD THAT THEY HEARD AN ACFT FLYING IN WX THEY DESCRIBED AS HVY RAIN, STRONG WINDS & LOW CLOUDS. ALSO, WITNESSES RPRTD THAT THE SOUND OF THE ENG WAS 'OSCILLATING' BEFORE THE PLANE CRASHED. NO PRE-ACDNT PART FAILURE OR MALFUNCTION WAS FOUND. ABT 11 WEST, THE SALISBURY WX WAS IN PART: 500' BKN, 1000' OVC, VIS 1/2 MI WITH RAIN & FOG.