HP Pavilion Slimline s3700y Desktop, 2.6GHz Athlon 64 X2 (B) 5000, 3GB, 320GB, DVD+/-R/RW 16X 12X +/... (NC689AAR) "t000" Questions

...returned, computer would not boot i had a powercut, when power returned, computer (HP Pavilion t000/t450) would not turn on. Green LED light was flashing, under the power cable. please help me. ...